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Approval and Promulgation of Implementation Plans; Arizona-- Maricopa County PM-10 Nonattainment Area; Serious Area Plan for Attainment of the 24-Hour PM-10 Standard and Contingency Measures
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[Federal Register: October 2, 2001 (Volume 66, Number 191)]
[Proposed Rules]
[Page 50251-50285]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr02oc01-21]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[AZ092-002; FRL-7067-5]
Approval and Promulgation of Implementation Plans; Arizona--
Maricopa County PM-10 Nonattainment Area; Serious Area Plan for
Attainment of the 24-Hour PM-10 Standard and Contingency Measures
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: EPA proposes to approve provisions of the Revised MAG 1999
Serious Area Particulate Plan for PM-10 for the Maricopa County
(Phoenix) Nonattainment Area, February 2000, including the revisions
submitted in June 2001 that address attainment of the 24-hour PM-10
national ambient air quality standard. We also propose to grant
Arizona's request to extend the Clean Air Act deadline for attaining
the 24-hour PM-10 standard in the Phoenix area from 2001 to 2006.
Finally, we propose to find that the plan provides for the
implementation of contingency measures for both the 24-hour and annual
PM-10 standards and to make several revisions to our previous proposal
on the MAG plan's provisions for the annual standard and our proposed
policy on attainment date extensions for serious PM-10 nonattainment
areas.
DATES: Comments on this proposal must be received in writing by
November 1, 2001. Comments should be addressed to the contact listed
below.
ADDRESSES: Comments should be mailed to: Frances Wicher, Office of Air
Planning (AIR-2), EPA Region 9, 75 Hawthorne Street, San Francisco, CA
94105-3901.
A copy of docket No. AZ-MA-00-001, containing the EPA technical
support document (EPA TSD) and other material relevant to this proposed
action, is available for public inspection at EPA's Region 9 office
during normal business hours.
A copy of the docket is also available for inspection at:
Arizona Department of Environmental Quality, Library, 3033 N. Central
Avenue, Phoenix, Arizona 85012. (602) 207-2217
Maricopa Association of Governments, 302 North 1st Street, Phoenix,
Arizona 85003. (602) 254-6300
Electronic Availability
This document and the Technical Support Document (TSD) are also
available as electronic files on EPA's Region 9 Web Page at http://
www.epa.gov/region09/air.
FOR FURTHER INFORMATION CONTACT: Frances Wicher, Office of Air Planning
(AIR-2), U.S. Environmental Protection Agency, Region 9, 75 Hawthorne
Street, San Francisco, California 94105. (415) 744-1248, email:
wicher.frances@epa.gov.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Summary of Today's Proposals
II. Background to Today's Proposals
A. PM-10 Air Quality in the Phoenix Area
B. Description of the MAG Plan's Provisions for Attaining the
24-Hour PM-10 Standard
C. Previous Actions on the Phoenix Serious Area PM-10 Plan
1. Annual Standard Proposal
2. Microscale Plan Partial Approval/Partial Disapproval
3. Arizona's Agricultural BMP General Permit Rule Approval
III. The CAA's Planning Requirements for Serious PM-10 Nonattainment
Areas
IV. The MAG Plan's Compliance with the CAA's Requirements for
Serious PM-10 Nonattainment Areas
A. Completeness of the SIP Submittals
B. Adequacy of the Transportation Conformity Budget
C. Emissions Inventory
D. Adequate Monitoring Network
E. Contribution to PM-10 Exceedances of Major Sources of PM-10
Precursors
F. Implementation of Reasonably Available and Best Available
Control Measures
1. Steps 1 and 2: Determination of significant sources
2. Step 3: Identification of potential BACM
3. Step 4: Implementation of RACM and BACM and inclusion of MSM
for each significant source category
a. Technology controls for on-road motor vehicle exhaust
b. Transportation control measures (TCMs) for on-road motor
vehicle exhaust and paved road dust
c. Nonroad engines
d. Paved road dust
e. Unpaved parking lots
f. Disturbed vacant lands
g. Unpaved roads
h. Construction sites and activities
i. Agricultural sources
j. Residential wood combustion
k. Secondary ammonium nitrate
l. MCESD's commitments to improve compliance and enforcement of
its fugitive dust rules
G. Attainment Date Extension
1. Apply for an extension
2. Demonstrate the impracticability of attainment by December
31, 2001
3. Complied with the commitments and requirements in the SIP
4. Include the most stringent measures
5. Demonstrate expeditious attainment
a. Air quality modeling
b. Control measures relied on for attainment
6. Other factors that EPA may consider
a. Nature and extent of nonattainment
b. Types and number of sources or other emitting activities
c. Population exposure to concentrations above the standard
d. Presence and concentration of potentially toxic substances in
the particulate
e. Technological and economic feasibility of controls
7. Conclusion on the extension request
H. Reasonable Further Progress and Quantitative Milestones
1. Reasonable further progress
2. Quantitative milestones
I. Contingency Measures
J. General SIP Requirements
V. CAA Requirements for BACM and Attainment Date Extension and EPA's
Guidance on Meeting these Requirements
A. Implementation of Best Available Control Measures
B. Extension of the Attainment Date beyond 2001
1. Apply for an attainment date extension
2. Demonstrate that attainment by 2001 is impracticable
3. Complied with all requirements and commitments in its
implementation plan
4. Demonstrate the inclusion of the most stringent measures
5. Demonstrate attainment by the most expeditious alternative
date practicable
VI. Administrative Requirements
I. Summary of Today's Proposals
First, we propose to approve the provisions in the Revised MAG 1999
Serious Area Particulate Plan for PM-10 for the Maricopa County
Nonattainment Area, February 2000, (``MAG plan'') including revisions
to that plan submitted in Maricopa County PM-10 Serious Area State
Implementation Plan Revision, Agricultural Best Management Practices,
June 2001, (collectively, ``the Maricopa County serious area plan'' or
``the plan'') that address attainment of the 24-hour PM-10 standard.\1\
Our proposed actions are based on our initial determination that the
Maricopa County serious area plan complies with the Clean Air Act's
(CAA) requirements for serious PM-10 nonattainment area plans.
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\1\ There are two separate national ambient air quality
standards for PM-10, an annual standardd of 50 µg/m\3\ and a
24-hour standard of 150 µg/m\3\. We proposed approval of the
MAG plan's annual standard provisions on April 13, 2000 at 65 FR
19964.
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Specifically, we propose to approve the following elements of the
plan as they pertain to the 24-hour standard:
The demonstration that the plan provides for
implementation of reasonably available control measures (RACM) and best
available control measures (BACM),
[[Page 50253]]
The demonstration that attainment by the CAA deadline of
December 31, 2001 is impracticable,
The demonstration that attainment will occur by the most
expeditious alternative date practicable, in this case, December 31,
2006,
The demonstration that the plan provides for reasonable
further progress and quantitative milestones,
The demonstration that major sources of PM-10 precursors
such as nitrogen oxides and sulfur dioxide do not contribute
significantly to air quality standard violations, and
The transportation conformity budget.
Second, we are proposing to grant Arizona's request to extend the
attainment date for the 24-hour PM-10 standard from December 31, 2001
to December 31, 2006. We make this proposal based on our determination
that the State has met the CAA's criteria for granting such extensions.
Third, we propose to find that the plan provides for the
implementation of contingency measures for both the 24-hour and annual
standards as required by the CAA.
Finally, we make several revisions to our April 13, 2000 proposed
approval of the annual standard provisions in the Maricopa County
serious area plan. These revisions involve:
Clarifications to our proposed policy on granting
attainment date extensions under CAA section 188(e),
Changes to Maricopa County Environmental Services
Department's (MCESD) commitments to further improve its fugitive dust
rule, Rule 310,
Changes to several other control measures, and
Evaluation of the plan's compliance with the BACM
requirement and most stringent measure requirement in CAA section
188(e) for the agriculture source category based on the State's
Agricultural Best Management Practices General Permit Rule.\2\
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\2\ Except for these limited number of revisions, we are not
reopening the comment period and are not soliciting comments on our
April 13, 2000 proposal.
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This preamble describes our proposed actions on the Phoenix area
plan and provides a summary of our evaluation of the plan. Our detailed
evaluation of the plan can be found in the technical support document
that accompanies this proposal. See ``Technical Support Document,
Notice of Proposed Rulemaking on the Serious Area PM-10 State
Implementation Plan for the Maricopa County PM-10 Nonattainment Area
Provisions for Attaining the 24-Hour Standard and Contingency
Measures,'' September 14, 2001 (EPA TSD). The EPA TSD is an integral
part of this proposal and should be reviewed prior to making comments.
A copy of the EPA TSD can be downloaded from our website or obtained by
calling or writing the contact person listed above.
II. Background to Today's Proposals
A. PM-10 Air Quality in the Phoenix Area
The Maricopa County (Phoenix) PM-10 nonattainment area is located
in the eastern portion of Maricopa County and encompasses the cities of
Phoenix, Mesa, Scottsdale, Tempe, Chandler, Glendale as well as 17
other jurisdictions and considerable unincorporated County lands.\3\ 40
CFR 81.303. The area is home to almost 3 million people.
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\3\ The Maaricopa nonattainment area also includes the town of
Apache Junction in Pinal County. Apache Junction is covered by a
separate air quality plan and will be addressed in a later action.
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The area violates both the annual and 24-hour PM-10 standards. In
1990, the area was designated nonattainment for PM-10 and classified as
moderate. In 1996, because of continuing violations of both PM-10
standards, the area was reclassified to serious and required to submit
a serious area plan by December 10, 1997. 61 FR 21372 (May 10, 1996).
The principal contributors to elevated PM-10 levels in the Phoenix
area are fugitive dust sources such as construction sites, unpaved
roads, vacant lots, agricultural sources, and paved road dust. Also
contributing to the PM-10 problem, but to a much lesser degree than
fugitive dust, are internal and external combustion sources including
directly-emitted PM-10 from automobiles, trucks, construction
equipment, buses, residential woodburning and industrial, commercial,
and residential use of natural gas and fuel oil. See MAG plan, p. 3-5.
There is a long and complex history to PM-10 air quality planning
in the Phoenix area. A summary of this history can be found in the
annual standard proposal at 65 FR 19964, 19965. A more detailed history
can be found in section 1 of the EPA TSD.
B. Description of the MAG Plan's Provisions for Attaining the 24-Hour
PM-10 Standard
Arizona has made several submittals to address the CAA requirements
for serious PM-10 nonattainment area plans for the Phoenix area. The
provisions for attainming the 24-hour PM-10 standard are found mainly
in three of these submittals: the 1997 Microscale plan,\4\ the 2000 MAG
plan, and the 2001 Best Management Practices (BMP) submittal.\5\ The
latter two documents are the subject of this proposal and are described
in more detail below. We have already acted on the Microscale plan, see
62 FR 41856 (August 4, 1997). We describe this plan and explain its
relationship to today's proposal in the next section.
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\4\ The 1997 Microscale plan is the Plan for Attainment of the
24-hour PM-10 Standard--Maricopa County PM-10 Nonattainment Area,
Arizona Department of Environmental Quality, May, 1997.
\5\ The other submittals contain rules and other control
measures relied on to provide for RACM, BACM, reasonable further
progress an attainment. These submittals include the commitments by
local jurisdictions to PM-10 control measures submitted in December
1997, revised MCESD Rules 310 and 310.01 submitted in March 2000,
Maricopa County's Residential Wood Burning Ordinance submitted in
January 2000, and the Agricultural Best Management Practices (BMP)
General Permit Rule submitted in July 2000.
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The first submittal is the Revised Maricopa Association of
Governments 1999 Serious Area Particulate Plan for PM-10 for the
Maricopa County Nonattainment Area, February 2000. This plan was
developed by the Maricopa Association of Governments (MAG), the lead
air quality planning agency in Maricopa County. The Arizona Department
of Environmental Quality (ADEQ) submitted this plan as a revision to
the Arizona State Implementation Plan (SIP) on February 16, 2000. We
refer to this plan in this document as the MAG plan or the revised MAG
plan; however, we occasionally use these terms to refer to the set of
documents that collectively comprise the Maricopa County serious area
PM-10 plan.
The second document is the Maricopa County PM-10 Serious Area State
Implementation Plan Revision, Agricultural Best Management Practices,
(BMP) June 2001, submitted in draft on April 26, 2001 and final on June
13, 2001. This SIP revision was developed by ADEQ. We refer to this
submittal as the BMP TSD.
The MAG plan contains a 1994 inventory and uses the urban airshed
model/limited chemistry version (UAM/LC) to model regional air quality
in 1995 as a base year and in 2006 as the attainment year for both the
annual and 24-hour standards. The MAG plan, however, relies primarily
on air quality modeling performed in the Microscale plan to evaluate
localized 24-hour exceedances.
The MAG plan, as revised by the BMP TSD, includes a BACM analysis
and a demonstration that attainment by 2001 is impracticable for both
the 24-hour and annual PM-10 standards. It also
[[Page 50254]]
includes, again for both PM-10 standards, the State's request for a
five-year extension of the attainment date, a demonstration that the
plan includes for the most stringent measures found in other states'
plans, and a demonstration of attainment by December 31, 2006.
The BMP TSD updates the MAG plan to reflect the State's adoption of
the Agricultural General Permit rule to control PM-10 from agricultural
sources in Maricopa County. It includes a background document which
provides the BACM demonstration for agricultural sources for both
standards, a revised demonstration of attainment and reasonable further
progress (RFP) for the 24-hour standard at two monitoring sites, and
revisions to the contingency measure provisions for both standards. It
also includes documentation quantifying emission reductions from the
Agricultural General Permit rule and documentation related to
implementing this rule.
C. Previous Actions on the Phoenix Serious Area PM-10 Plan
We have taken three actions related to the Phoenix Serious Area PM-
10 plan: the proposed approval of the MAG plan's provisions for the
annual standard, the partial approval/ partial disapproval of the 1997
Microscale plan, and the approval of Arizona's Agricultural BMP General
Permit rule. With today's proposal, we have now proposed action on all
elements of the Maricopa County serious area PM-10 plan.
1. Annual Standard Proposal
On April 13, 2000, we proposed to approve the MAG plan's provisions
for attainment of the annual PM-10 standard. See 65 FR 19964.\6\
Specifically, we proposed to approve for the annual standard the
provisions for implementation of RACM and BACM, the demonstration that
attainment by 2001 is impracticable, the demonstration that attainment
will occur by the most expeditious alternative date, the RFP
demonstration, the quantitative milestones, and the conformity budget.
We also proposed to grant an extension of the attainment date from 2001
to 2006 based on our proposed determination that Arizona had met the
CAA criteria for granting such an extension.
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\6\ In the annual standard propsoal and in the EPA TSD for
today's proposal, we discuss the legal basis for separating the
proposed approvals for the 24-hour and annual standards and the
practical reasons we chose to do so. See 65 FR 19964, 19969 and
section 3 of the EPA TSD. We intent, however, to finalize actions on
both standards in a single rulemaking in early 2002.
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In April 2000 preamble, we also proposed to approve the base year
regional emissions inventory required by CAA section 172(c)(3), MCESD's
Rules 310 and 310.01, Maricopa County's Residential Woodburning
Ordinance, and the commitments by the cities, towns, and County of
Maricopa, ADEQ, MAG, and other State and local agencies to implement
various PM-10 control measures. These proposals were applicable to both
the annual and 24-hour PM-10 standards and thus are not being repeated
today.
2. Microscale Plan Partial Approval/Partial Disapproval
The attainment demonstration for the 24-hour standard in the
Maricopa County serious area plan has both a local modeling component
and a regional modeling component. Portions of the local or microscale
component are found in the Microscale plan, the 2000 MAG plan, and the
BMP TSD. The regional component is contained completely within the 2000
MAG plan.
Most of the technical evaluation for the microscale component is
contained in the Microscale plan which was submitted to us in May 1997.
It evaluates exceedances of the 24-hour PM-10 standard at four Phoenix
area monitoring sites: Salt River, Maryvale, Gilbert, and West
Chandler.
This evaluation involved developing local, day-specific inventories
and dispersion modeling to determine source contributions to
exceedances at each site. The evaluation showed that the primary
contributors to 24-hour exceedances in the Phoenix area are local
fugitive dust sources such as construction sites, agricultural fields
and aprons, vacant lots, unpaved roads and parking lots, and
earthmoving operations. The Microscale plan also described the type of
controls necessary to show attainment at each site although the plan
only assured the implementation of such controls on construction-
related sources.
We approved the Microscale plan in part and disapproved it in part
on August 4, 1997 (62 FR 41856). We approved the attainment and RFP
demonstrations for the Salt River and Maryvale sites because the plan
demonstrated expeditious attainment at these sites; however, we
disapproved these demonstrations for the West Chandler and Gilbert
sites because the plan did not demonstrate attainment at them. Because
attainment demonstrations at the Salt River and Maryvale sites were
already approved, ADEQ limited its subsequent microscale work to
developing approvable demonstrations for the Gilbert and West Chandler
sites. Our proposal today is also limited to these two sites.
To evaluate the provisions for the 24-hour PM-10 standard in the
MAG plan, we are relying to a large extent on our previous evaluation
of the Microscale plan. Except for the findings related to the
implementation of BACM, we have not reevaluated the 24-hour standard
provisions that we have already found adequate or approved as part of
our actions on the Microscale plan.
More information on the Microscale plan can be found in section 1
of the EPA TSD and our proposed and final rulemakings on it. 62 FR
31025 (June 6, 1997) and 62 FR 41856 (August 4, 1997).
3. Arizona's Agricultural BMP General Permit Rule Approval
The analysis done for the Microscale plan revealed for the first
time how significant a contribution agricultural sources make to
exceedances of the 24-hour PM-10 standard in the Phoenix area. See
Microscale plan, pp. 18-19. In order to develop adequate controls for
this source, Arizona passed legislation in 1997 establishing an
Agricultural Best Management Practices (BMP) Committee and directing
the Committee to adopt by rule by June 10, 2000, an agricultural
general permit specifying best management practices for reducing PM-10
from agricultural activities. The legislation also required that
implementation of the agricultural controls begin by June 10, 2000 with
an education program and full compliance with the rule be achieved by
December 31, 2001. See Arizona Revised Statutes (A.R.S.) 49-457.
In September 1998, the State submitted the legislation. On June 29,
1999, we approved it as meeting the RACM requirements of the CAA.\7\ 64
FR 34726.
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\7\ In 1998, we promulgated a moderate area PM-10 federal
implementation plan (FIP) for the Phoenix area. 63 FR 41326 (August
3, 1998). One of the measures in this FIP was our commitment to
adopt RCM for agricultural sources, RACM being the primary control
requirement for moderate PM-10 nonattainment areas. Arizona
submitted the BMP legislation in 1998 as, among other things, a
substitute for our FIP RACM commitment. Before we could withdraw our
FIP RACM commitment and replace it with the State's legislation, we
had to first find that the legislation was at least RACM, hence our
initial determination that it was at least RCM. For further
information on this legislation and its relationship to the history
of PM-10 planning in the Phoenix area, see the ``Implementation of
BACM and Inclusion of MSM for Agricultural Sources'' section in the
EPA TSD.
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While we approved the legislation as RACM, it was the State's
intent that it also serve as BACM and MSM for agricultural sources in
the serious area
[[Page 50255]]
PM-10 plan. Therefore, in our annual standard proposal, we evaluated
and proposed to find that the legislation met the CAA BACM and MSM
requirements for the agricultural source category. 65 FR 19964, 19981.
After a series of meetings during 1999 and 2000, the Agricultural
BMP Committee adopted the agricultural general permit rule and
associated definitions, effective May 12, 2000, at Arizona
Administrative Code (AAC) R18-2-610, ``Definitions for R18-2-611,'' and
611, ``Agricultural PM-10 General Permit; Maricopa PM10 Nonattainment
Area'' (collectively, general permit rule). The State submitted the
general permit rule in July 2000 and its analysis quantifying the
emission reductions expected from the rule and the demonstration that
the rule meets the CAA's RACM, BACM and MSM requirements in the June
2001 BMP TSD. We proposed to approve the rule as meeting the CAA
requirement for RACM on June 29, 2001 and signed the final approval on
September 10, 2001. See 66 FR 34598.
We are today withdrawing our proposed finding in the annual
standard proposal that the State legislation provides for the
implementation of BACM and MSM for agricultural sources for the annual
standard. 66 FR 19964, 19981. In its place we are proposing to find
that the General Permit rule provides for the implementation of BACM
and MSM for agricultural sources for the annual standard. This proposal
is based on our analysis, summarized later, of the rule and the State's
demonstrations in the BMP TSD and is in addition to our proposed
finding that the rule provides for the implementation of BACM and MSM
for the 24-hour standard.
III. The CAA's Planning Requirements for Serious PM-10
Nonattainment Areas
The Phoenix area is a PM-10 nonattainment area that has been
reclassified to serious because it failed to attain by the moderate
area attainment date of December 31, 1994. Such an area must submit,
within 18 months of the reclassification, revisions to its
implementation plan that address the CAA requirements for serious PM-10
nonattainment areas. CAA section 189(b)(2). These requirements are:
(a) assurances that the BACM, including best available control
technology (BACT) for stationary sources, for the control of PM-10
shall be implemented no later than 4 years after the area is
reclassified (CAA section 189(b)(1)(B)); \8\
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\8\ When a moderate area is reclassified to serious, the
requirement to implement RACM in section 189(a)(1)(C) remains and is
augmented by the requirement to implement BACM. Thus, a serious area
PM-10 plan must, in addition to BACM, provide for the implementation
of RACM as expeditiously as practicable to the extent that the RACM
requirement has not been satisfied in the area's moderate area plan.
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(b) assurances that BACT on major stationary sources of PM-10
precursors shall be implemented no later than 4 years after the area is
reclassified except where EPA has determined that such sources do not
contribute significantly to exceedances of the PM-10 standards (CAA
section 189(e));
(c) a demonstration (including air quality modeling) that the plan
will provide for attainment as expeditiously as practicable but no
later than December 31, 2001 or where the State is seeking an extension
of the attainment date under section 188(e), a demonstration that
attainment by December 31, 2001 is impracticable and that the plan
provides for attainment by the most expeditious alternative date
practicable (CAA sections 188(c)(2) and 189(b)(1)(A));
(d) quantitative milestones which are to be achieved every 3 years
and which demonstrate reasonable further progress toward attainment by
the applicable attainment date (CAA sections 172(c)(2) and 189(c)); and
(e) a comprehensive, accurate, current inventory of actual
emissions from all sources of PM-10 (CAA section 172(c)(3)).
Serious area plan must also provide for the implementation of
contingency measures if the area fails to make RFP or attain by its
attainment deadline. These contingency measures are to take effect
without further action by the State or the Administrator. CAA section
172(c)(9).
Serious area PM-10 plans must also meet the general requirements
applicable to all SIPs including reasonable notice and public hearing
under section 110(l), necessary assurances that the implementing
agencies have adequate personnel, funding and authority under section
110(a)(2)(E)(i) and 40 CFR 51.280; and the description of enforcement
methods as required by 40 CFR 51.111.
We have issued a General Preamble\9\ and Addendum to the General
Preamble\10\ describing our preliminary views on how the Agency intends
to review SIPs submitted to meet the CAA's requirements for PM-10
plans. The General Preamble mainly addresses the requirements for
moderate areas and the Addendum, the requirements for serious areas.
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\9\ ``State Implementation Plans; General Preamble for the
Implementation of Title I of the Clean Air Act Amendments of 1990,''
57 FR 13498 (April 16, 1992) and 57 FR 18070 (April 28, 1992).
\10\ ``State Implementation Plans for Serious PM-10
Nonattainment Areas, and Attainment Date Waivers for PM-10
Nonattainment Areas, and Attainment Date Waivers for PM-10
Nonattainment Areas Generally; Addendum to the General Preamble for
the Implementation of Title I of the Clean Air Act Amendments of
1990,'' 59 FR 41998 (August 16, 1994)
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IV. The MAG Plan's Compliance with the CAA's Requirements for
Serious PM-10 Nonattainment Area
The following sections present a condensed discussion of our
evaluation of the MAG plan's compliance with the applicable CAA
requirements for attaining the 24-hour PM-10 standard. Our complete
evaluation is found in the EPA TSD for this proposal. We strongly urge
anyone wishing to comment on this proposal to first review the TSD
before preparing comments. A copy of the TSD can be downloaded from our
website or obtained by calling or writing the contact person listed
above.
A. Completeness of the SIP Submittals
CAA section 110(k)(1)(B) requires us to determine if a SIP
submittal is complete within 60 days of its receipt. This completeness
review allows us to quickly determine if the submittal includes all the
necessary items and information we need to take action on it. We make
completeness determinations using criteria we have established in 40
CFR part 51, appendix V.
We found ADEQ's February 16, 2000 submittal of the final revised
MAG serious area PM-10 plan complete on February 25, 2000. See letter,
David P. Howekamp, EPA, to Jacqueline Schafer, ADEQ.
We also found ADEQ's June 13, 2001 submittal of the BMP TSD
complete on August 10, 2001. See letter, Jack Broadbent, EPA, to
Jacqueline Schafer, ADEQ.
B. Adequacy of the Transportation Conformity Budgets
CAA Section 176(c) requires that federally-funded or approved
transportation plans, programs, and projects in nonattainment areas
``conform'' to the area's air quality implementation plans. Conformity
ensures that federal transportation actions do not worsen an area's air
quality or interfere with its meeting the air quality standards. We
have issued a conformity rule that establishes the criteria and
procedures for determining
[[Page 50256]]
whether or not transportation plans, programs, and projects conform to
a SIP. See 40 CFR part 93, subpart A.
One of the primary tests for conformity is to show transportation
plans and improvement programs will not cause motor vehicle emissions
higher than the levels needed to make progress toward and meet the air
quality standards. The motor vehicle emissions levels needed to make
progress toward and meet the air quality standards are set in an area's
attainment and/or RFP plans and are known as the ``emissions budget for
motor vehicles.'' Emissions budgets are established for specific years
and specific pollutants. See 40 CFR 93.118(a).
Before an emissions budget in a submitted SIP revision can be used
in a conformity determination, we must first determine that it is
adequate. The criteria by which we determine adequacy of submitted
emission budgets are outlined in our conformity rule in 40 CFR
93.118(e)(4). A finding of adequacy does not approve an emissions
budget, it simply allows states to begin to use the budget in
conformity determinations pending our action on the overall SIP.
The MAG plan establishes a mobile source emissions budget of 59.7
mtpd. This regional budget is applicable to both the annual and 24-hour
PM-10 standards. The on-road mobile source portion of the budget, which
includes emissions from reentrained road dust, vehicle exhaust, and
travel on unpaved roads, is 58.6 mtpd. The road construction dust
portion of the budget is 1.1 mtpd. MAG plan, p. 8-13.
On March 30, 2000, we found adequate for transportation conformity
purposes this motor vehicle emissions budget. Our adequacy finding is
documented in section II of the EPA TSD for the annual standard. As a
result of our adequacy finding, MAG and the Federal Highway
Administration are now required to use this budget in all conformity
analyses.
As discussed later in this preamble, we are proposing to approve
both the attainment and reasonable further progress demonstrations for
the 24-hour standard in the Maricopa County serious area PM-10 plan.
The 59.7 mtpd budget is consistent with these demonstrations. We,
therefore, propose to approve it as the motor vehicle emissions budget
for the 24-hour PM-10 standard under CAA section 176(c).
C. Emissions Inventory
CAA section 172(c)(3) requires that nonattainment area plans
include a comprehensive, accurate, and current inventory of actual
emissions from all sources in the nonattainment area. To meet this
requirement Arizona submitted a 1994 base year inventory as part of the
MAG plan. See MAG plan, Appendix A, Exhibit 6. We proposed to approve
this inventory as meeting the requirements of section 172(c)(3) in our
proposal on the annual standard provisions. See 65 FR 19964, 19970.
In the Phoenix nonattainment area, both regional and microscale
modeling inventories are needed to accurately reflect the sources that
are contributing to 24-hour PM-10 ambient levels. The regional modeling
inventories were derived from the 1994 base year inventory and are the
same for the annual and 24-hour standards. We proposed to find these
regional modeling inventories to be acceptable as part of annual
standard provisions. See 65 FR 19964, 19985-19986.
ADEQ developed microscale and subregional inventories for 1995 (the
modeling base year) for the West Chandler and Gilbert microscale sites.
See Microscale plan, Appendix A, Chapter 4 and MAG plan, Appendix C,
Exhibit 3, Chapter 3. In the 1997 Microscale plan, ADEQ also developed
1995 inventories for the two other microscale sites, Maryvale and Salt
River. See Microscale plan, Appendix A, Chapters 4 and 6. We evaluated
the 1995 inventories for all four sites as part of our action on the
overall Microscale plan. See 62 FR 31025, 31030 (June 6, 1997). These
microscale inventories are specialized modeling inventory and is not
intended to satisfy the CAA section 172(c)(3) requirement.\11\
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\11\ The microscale inventories include only sources within a
small area surrounding each monitor rather than all sources within
the entire nonattainment area as requirement in CAA section
172(c)(3).
---------------------------------------------------------------------------
We discuss emissions inventories in this preamble and in the EPA
TSD in order to present a complete technical review of the Maricopa
County serious area plan's provisions for attainment of the 24-hour
standard. Emissions inventories play a fundamental role in air quality
modeling, and CAA section 189(b)(1)(A) requires attainment
demonstrations in PM-10 serious area plan to be based on modeling. We
cannot find this modeling, or the attainment demonstrations that are
derived from it, approvable without first finding that the underlying
emissions inventories are adequate. We are not, however, proposing any
actions today on the inventories relied on in the Maricopa County
serious area plan for demonstrating attainment of the 24-hour standard
because, as discussed above, we have already either proposed to approve
them or found them to be acceptable.
D. Adequate Monitoring Network
We discuss the adequacy of the monitoring network in this preamble
solely to support our finding that the plan appropriately evaluates the
PM-10 problem in the Phoenix area. Reliable ambient data is necessary
to validate the base year air quality modeling which in turn is
necessary to assure sound attainment demonstrations.
The CAA requires states to establish and operate air monitoring
networks to compile data on ambient air quality for all criteria
pollutants. Section 110(a)(2)(B)(i). Our regulations in 40 CFR 58
establishes specific regulatory requirements for operating air quality
surveillance networks to measure ambient concentrations of PM-10,
including measurement method requirements, network design, quality
assurance procedures, and in the case of large urban areas, the minimum
number of monitoring sites designated as National Air Monitoring
Stations (NAMS).
Ambient networks, however, do not need to meet all our regulations
to be found adequate to support air quality modeling. A good spatial
distribution of sites, correct siting, and quality-assured and quality-
controlled data are the most important factors we consider when
evaluating the monitoring network for air quality modeling.
Nonattainment area plans developed under title I, part D of the Clean
Air Act are not, in general, required to address how the area's air
quality network meets our monitoring regulations. These plans are
submitted too infrequently to serve as the vehicle for assuring that
monitoring networks remain current.
The base year for the MAG plan is 1995. In 1995, there were 16
monitoring sites operated by either MCESD or ADEQ that collected PM-10
data in the Phoenix area, three designated as NAMS, five designated as
state/local monitoring stations, and eight designated as special
purpose monitors. All of the sites were operated in accordance with our
regulations in 1995. Figure 3-2 in the MAG plan lists the names of the
sites and their locations in the Phoenix area as of April 1999. Most of
these PM-10 monitoring sites were sited as neighborhood scale with an
objective of assessing population exposure. Given the nature of the
emission sources in the Phoenix area, which are mostly local fugitive
dust sources, we believe this is an appropriate focus of the network.
The 24-hour attainment demonstration in the MAG plan relies, in
part, on showing attainment at four specific monitoring sites. These
sites
[[Page 50257]]
were chosen to evaluate the type and mix of sources thought to be
contributing to elevated 24-hour PM-10 levels: Salt River for its
proximity to industrial sources; West Chandler for its nearby highway
construction; Maryvale for its residential area coupled with land
disturbing activities due to the construction of a park, and Gilbert
for its proximity to agricultural land. In 1995 these sites recorded
the highest and most frequent exceedances of the 24-hour PM-10
standard. They are also representative of similar areas in the Phoenix
area that may not have monitoring sites.
Based on our evaluation, we have concluded that the monitoring
network operated by the MCESD and ADEQ in 1995 was adequate to support
the air quality modeling in the MAG plan. The network utilized EPA
reference or equivalent method monitors and both agencies have EPA-
approved quality assurance plans in place.
E. Contribution to PM-10 Exceedances of Major Sources of PM-10
Precursors
CAA section 189(e) requires a state to apply the control
requirements applicable to major stationary sources of PM-10 to major
stationary sources of PM-10 precursors, unless we determine such
sources do not contribute significantly to PM-10 levels in excess of
the NAAQS in the area. For the serious area plan, a major source is one
that emits or has the potential to emit over 70 English tons per year
(tpy) of sulfur oxides (SOX), nitrogen oxides
(NOX), or ammonium.
PM-10 precursors react in the atmosphere to form secondary
particulate, secondary because it is not directly emitted from the
source. The MAG plan does not provide specific information on the
impact of major precursor sources on Phoenix PM-10 levels; however, it
does provide sufficient information on the contribution of total
secondary particulates to PM-10 levels and the emissions from major
precursor sources to estimate the impact.
We estimate that major stationary sources contribute at most 0.61
µg/m\3\ to 24-hour PM-10 levels in the Phoenix area. See EPA
TSD section, ``BACT for Major Stationary Sources of PM-10 Precursors.''
We estimated this contribution by assuming that the major stationary
sources' contribution to secondary levels is proportional to their
presence in the inventory. We believe that this assumption is
reasonable given the very small presence of major stationary sources in
the precursor inventory and the small contribution total secondaries
make to PM-10 levels in Phoenix. Moreover, secondary particulate takes
hours to form in ambient air from its precursors. By the time secondary
particluate is formed, the precursors are well mixed in the ambient
air, so localized, disproportionate impacts by major sources of PM-10
precursors are very unlikely.
This contribution is well below our proposed 5 µg/m\3\
significance level.\12\ However, independent of this fact, we believe
that so small a contribution--less than 0.4 percent of the 24-hour PM-
10 standard of 150 µg/m\3\--is truly insignificant by any
measure for the Phoenix area. PM-10 levels above the 24-hour standard
in Phoenix are almost exclusively caused by a few large source
categories of fugitive dust. It is controls on these sources that are
the key to expeditious attainment and not controls on trivial
contributors such as major stationary sources of PM-10 precursors.
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\12\ The MAG plan demonstrates that the 5µg/m\3\ is the
appropriate level for determining which categories are significant
for the BACM requirement for the 24-hour standard; therefore, we
believe that it is an appropriate level for us to adopt here.
---------------------------------------------------------------------------
Based on their negligible impact on ambient PM-10 levels, we
propose to determine that major sources of PM-10 precursors do not
contribute significantly to PM-10 levels which exceed the 24-hour
standard in the Phoenix area; therefore, pursuant to CAA section
189(e), BACT need not be applied to major sources of PM-10 precursors.
F. Implementation of Reasonably Available and Best Available Control
Measures
CAA section 189(b)(1)(B) requires that a serious area PM-10 plan
provide for the implementation of BACM within four years of
reclassification to serious. For Phoenix, this deadline is June 10,
2000. Under our applicable guidance, BACM must be applied to each
significant area-wide source category. Addendum at 42011. As discussed
in section V of this preamble, we have established a four-step process
for evaluating BACM in serious area PM-10 plans.
1. Steps 1 and 2: Determination of Significant Sources
The first step in the BACM analysis is to develop a detailed
emissions inventory of PM-10 sources and source categories that can be
used in modeling to determine their impact on ambient air quality.
Addendum at 42012. The second step is use this inventory in air quality
modeling to evaluate the impact on PM-10 concentrations over the
standards of the various sources and source categories to determine
which are significant.
The development of the detailed emissions inventories is discussed
in a preceding section. The MAG plan uses three modeling studies of PM-
10 sources in the Phoenix area to identify significant source
categories. One of these studies evaluated significant sources using
chemical mass balance (CMB) modeling performed on monitoring samples
collected at 6 sites in 1989-1990. The two other studies evaluated
significant sources using dispersion modeling of sources around 6
monitoring sites using data from 1992 through 1995.\13\
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\13\ These studies are ``The 1989-90 Phoenix PM-10 Study'',
Desert Research Institute, April 1991; ``Particulate Control Measure
Feasibility Study,'' Sierra Research, January 1997; and the
Microscale plan.
---------------------------------------------------------------------------
From these evaluations, the MAG plan identifies 8 significant
source categories and 12 insignificant source categories. MAG plan, p.
9-6.
The final list of significant source categories in the MAG plan
does not distinguish between those categories that are significant for
the 24-hour standard and those that are significant for the annual
standard; although previous studies have shown that some source
categories are significant only for one or the other standard. Because
the MAG plan does not distinguish significant source categories between
the two standards, we treat each of the listed significant source
categories as significant for the 24-hour standard.
For the 24-hour standard, the MAG plan demonstrates that its
selection of significant source categories is appropriate by showing
that controls on the de minimis source categories would not result in
attainment of the 24-hour standard by 2001. For a detailed description
of this demonstration, see MAG plan, pp. 9-12 to 9-15 and the EPA TSD
section ``BACM Analysis--Step 2, Model to Identify Significant
Sources.''\14\
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\14\ In this de minimus demonstration, certain source categories
vacant land, unpaved roads, agricultural sources, and unpaved
parking--were assumed to be uncontrolled at the end of 2001. See MAG
plan, Tables 9-b and 9-c. These categories will in fact be subject
to BACM by then. By not including controls on these categories in
the de minimis demonstration, the gap between nonattainment and
attainment of the 24-hour standard in 2001 is much larger than it
should be and thus, the de minimis determination for the 24-hour
standard is suspect.
To check if the selected de minimis categories are truly de
minimis under the correct control assumptions, we redid the
determination incorporating the appropriate level of control for
each source category. We concluded from this reanalysis that the MAG
plan's selected de minimis threshold is in fact appropriate and the
identified de minimis categories are indeed de minimis and are
appropriately excluded from the BACM analysis. See EPA TSD, section
``BACM Analysis--Step 2, Model to Identify Significant Sources.''
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[[Page 50258]]
The 8 significant source categories are:
1. Paved road travel
2. Unpaved road travel (includes unpaved parking lots)
3. Industrial paved road travel (paved and unpaved)
4. Construction site preparation (includes disturbed vacant lots
that are not undergoing construction)
5. Agricultural tilling (includes all agricultural sources)
6. Residential wood combustion
7. On-road and non-road motor vehicle exhaust
8. Secondary ammonium nitrate MAG Plan, Table 9-1.
The 12 de minimis source categories are:
1. Stationary point sources
2. Fuel combustion (excluding residential wood combustion)
3. Waste/open burning
4. Agricultural harvesting
5. Cattle feedlots
6. Structural/vehicle fires
7. Charbroiling/frying meat
8. Marine vessel exhaust
9. Airport ground support exhaust
10. Railroad locomotive exhaust
11. Windblown from fluvial channels
12. Wild fires
MAG plan, Table 9-a. The plan notes that several de minimis source
categories (e.g., stationary point sources, waste/open burning,
agricultural harvesting, charbroiling) are already subject to control
or will be controlled in the future. MAG plan, p. 9-12.
We propose to find that the MAG plan has not excluded any source
categories that should be considered significant from its list of
significant source categories. The plan presents acceptable modeling to
evaluate the impact of various PM-10 sources and source categories on
PM-10 levels and to derive a comprehensive and conservative list of
significant source categories.
2. Step 3: Identification of Potential BACM
In preparing the list of candidate BACM, MAG reviewed our guidance
documents on BACM, other EPA documents on PM-10 control, as well as PM-
10 plans from other serious PM-10 nonattainment areas in the western
United States. MAG also evaluated controls proposed during public
comment. MAG plan, pp. 9-24 through 9-29; MAG Plan, Appendix D, Exhibit
1, ``Response to Public Comments, January 31, 2000 Public Hearing'';
and BMP TSD, pp. 9 through 27.
The MAG plan appropriately screened the list of candidate BACM to
eliminate measures that did not apply to significant source categories
in the area, were technologically infeasible for the area because they
would not reduce PM-10 emissions, or duplicated other measures on the
list. The plan also provides cost effectiveness estimates for each of
the candidate BACM. MAG plan, pp. 9-30 through 9-39; and BMP TSD, pp. 9
through 27.
We propose to find that the Maricopa County serious area PM-10 plan
identified and evaluated potential BACM for the Maricopa area
consistent with our guidance. As we will discuss below in our
evaluations of the implementation of BACM for each significant source
category, we do not believe that the plan left out any candidate BACM.
Overall, the plan presents one of the most comprehensive lists of
potential BACM ever produced.
3. Step 4: Implementation of RACM and BACM and inclusion of MSM for
Each Significant Source Category
In the following sections, we review the results of the Maricopa
County serious area plan's BACM analysis. To present these results, we
have grouped the emission generating activities that comprise the MAG
plan's significant categories slightly differently from the plan, e.g.,
we have addressed separately construction activities and disturbed
vacant lands which are both included in the MAG plan's significant
category of construction site preparation.\15\ We have done this to
make our evaluations of the plan's provisions for the implementation of
BACM and inclusion of MSM clearer and thus, we believe, more
understandable. However, despite the method of presentation, we have
addressed the MAG plan's provisions for implementing RACM and BACM for
each of the plan's significant source categories.
---------------------------------------------------------------------------
\15\ MAG plan uses this grouping despite the fact that disturbed
vacant lands include lands that are disturbed for reasons other than
construction activity.
---------------------------------------------------------------------------
Also, because of the substantial overlap in the source categories
and controls evaluated for BACM and those evaluated for MSM, we present
our evaluation of the MAG plan's provisions for including MSM alongside
our evaluation of the provisions for implementing RACM and BACM for
each significant source category.
Controls on a number of significant source categories are in
MCESD's fugitive dust rules, Rule 310 and Rule 310.01. MCESD has made
extensive commitments to improve compliance and enforcement of these
rules to assure that they achieve the emission reductions necessary for
expeditious attainment. These commitments are an important component of
our proposed finding that the MAG plan provides for implementation of
RACM and BACM and inclusion of MSM. We discuss them at the end of this
section.
As discussed above, the MAG plan made no distinction between
significant sources for the annual standard and those for the 24-hour
standard and, as a result, it made no distinction between BACM and MSM
for the annual standard and those for the 24-hour standard. We have
already extensively reviewed the MAG plan's BACM and MSM provisions for
the annual standard and these reviews are applicable to the 24-hour
standard. Thus, except for clarifying and/or updating information on a
few measures, we have not revised our evaluations of BACM and MSM for
most of the significant source categories. Four categories--on-road
engines (technology controls), nonroad engines, unpaved roads and
construction dust--have undergone moderate changes.
Our analysis of the agricultural source category has changed
substantially from the annual standard proposal. As discussed above, we
based our review in the annual standard proposal on the State's
legislation requiring the adoption of measures for agriculture. Since
then, the State has adopted the agricultural general permit rule and
has submitted revisions to the Maricopa County serious area plan
containing the demonstration that the general permit rule represents
BACM and MSM. For today's proposal, we have based our review of BACM
and MSM for the agricultural sources on the general permit rule and the
State's additional documentation. Our revised analysis applies to both
the annual and 24-hour standards.
a. Technology Controls for On-road Motor Vehicle Exhaust
This category includes tailpipe and tire wear emissions of primary
PM-10 from on-road motor vehicles. On-road motor vehicles include both
gasoline and diesel-powered passenger cars, light, medium, and heavy
duty trucks, buses, and motorcycles.
The suggested technology-based measures for controlling emissions
from on-road motor vehicle exhaust fall into one of five categories:
new emission standards, inspection and maintenance (I/M) programs,
fuels, programs to encourage alternative fueled vehicle usage, and
programs to accelerate fleet
[[Page 50259]]
turnover. In total, the MAG plan considers 22 technology-based control
measures. See MAG plan, Table 5-2. We believe this list is complete and
propose to find that the MAG plan evaluates a comprehensive set of
potential technology-based controls for on-road motor vehicle exhaust
emissions including the potentially most stringent measures from other
states.
For gasoline vehicles, Arizona has implemented one of the nation's
best and most comprehensive enhanced I/M programs including expanding
the program to areas surrounding Phoenix; has adopted its own Cleaner
Burning Gasoline program which mandates the use of either Phase II
federal reformulated gasoline or California reformulated gasoline; and
mandates federal, state, county, and municipal governments to convert
their fleets to alternative fuels. MAG plan, pp. 7-2 through 7-24.
Arizona has instituted a heavy-duty diesel I/M program, will
require pre-1988 HDDV registered in the Phoenix nonattainment area to
meet 1988 federal emission standards starting in 2004, has established
a voluntary vehicle repair and retrofit program to encourage
retrofitting and overhaul of heavy duty diesel engines to reduce
emissions, and has limited diesel sulfur content to 500 parts per
million (ppm). MAG plan, Chapter 7.
As noted before, Arizona has in place a comprehensive programs to
address on-road motor vehicle emissions. With the additional measures
in the MAG plan (including a more stringent diesel I/M program and
measures both encouraging and requiring diesel fleet turnover), the
overall mobile source program is strengthened and goes beyond the
existing program. Both strengthening and expanding existing programs
are key criteria for demonstrating the implementation of BACM. See
Addendum at 42013. Where the MAG plan has rejected potential BACM, it
provides a reasoned and acceptable justification for the rejection. See
EPA TSD, Table ORM-3 in the section ``Implementation of BACM and MSM
for On-Road Motor Vehicle Exhaust and Paved Road Dust (Technology
Standards and Fuels).''
The MAG plan identified just a few measures from other areas as
potential MSM. These measures have either been adopted or we have
concluded that the measure need not be included to assure the inclusion
of MSM.
The California Air Resources Board's diesel fuel standards (CARB
diesel) is one of the few identified motor vehicle controls not adopted
by the State.\16\ The plan identifies this measure as a potential MSM.
MAG plan, Table 10-7. The MAG plan claims that the measure is
unreasonable on a cost basis. MAG plan, p. 9-46.
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\16\ Arizona has already adopted half of the CARB diesel
standards, the 500 ppm sulfur limit. The other CARB diesel standard
is a limit on the aromatic hydrocarbon content of no more than 10
percent by volume. CARB, Fact Sheet on California Diesel Fuel, March
1997. Also, in January 2001, we established a new diesel fuel sulfur
limit of 15 ppm as part of our overall program to control emissions
from heavy duty diesel vehicles. They new limit which will apply to
Arizona will be fully in place by September, 2006. 66 FR 5002
(January 8, 2001).
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Based on information in the Microscale plan, emissions from on-road
motor vehicle are not implicated in 24-hour exceedances in the Phoenix
area. Microscale plan, pp. 17-19. All currently available evidence is
that 24-hour exceedances are caused by local fugitive dust sources and
controls on these sources alone will result in the earliest practicable
date for attainment of the 24-hour PM-10 standard in the Phoenix area.
Microscale plan, pp. 17-19. Because implementation of CARB diesel would
not result in earlier attainment and thus unnecessary for expeditious
attainment, we propose to find that the MAG plan provides for the
inclusion of MSM to our satisfaction absent the adoption and
implementation of CARB diesel.
Except for one, all the adopted BACM and MSM were implemented by
June 10, 2000, the BACM implementation deadline for the Phoenix area.
The exception is the requirement that pre-1988 heavy duty diesel
vehicles registered in the nonattainment area meet 1988 federal
emission standards. This measure will not be fully implemented until
January 1, 2004 in order to provide sufficient lead time for
modification or replacement of the non-complying heavy duty diesel
vehicles.
We, therefore, propose to find that the combination of on-road
motor vehicle technology controls and transportation control measures
(described in the next section) in the MAG plan provides for the
implementation of RACM and BACM and the inclusion of MSM for on-road
motor vehicle exhaust for the 24-hour standard.
Since the annual standard proposal was published in April 2000,
changes have been made to two on-road motor vehicle controls that were
included in that proposal: the remote sensing (RSD) program in the
State's vehicle emissions inspection program (VEIP) and changes to the
State's incentives for purchase of alternatively-fueled vehicles or
conversions to alternatively-fueled vehicles.
In 2000, the Arizona legislature converted the RSD program from a
regulatory program to a pilot program because of its high cost per ton
of emissions reduced \17\ In July 2001, Arizona submitted a SIP
revision that included all changes to State's VEIP program that had
been made since we last approved it in 1995, including the changes to
the RSD program. 2001 I/M SIP submittal, p. 26. We consider this I/M
program submittal to be Arizona's current statement of what elements
constitute its VEIP.
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\17\ ADEQ, Final Arizona State Implementation Plan Revision,
Basic and Enhanced Vehicle Emissions Inspection/Maintenance Program,
June 2001 (``2001 I/M SIP submittal''), p. 26.
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The RSD program is not credited in the RFP or attainment
demonstrations for the annual standard. The State justifies its
revision to this program based on the implementation cost of the
unrevised program, that is, they have determined that the unrevised
program was economically infeasible. We believe that this change to the
overall on-road motor vehicle control program in the MAG plan do not
adversely affect our previously proposed finding that the plan provides
for the implementation of RACM and BACM and the inclusion of MSM for
this source category for the annual standard found at 65 FR 19964,
19972.
b. Transportation Control Measures (TCMs) for On-road Motor Vehicle
Exhaust and Paved Road Dust
TCMs can reduce PM-10 emissions in both the on-road motor vehicle
exhaust and paved road dust source categories by reducing vehicle miles
traveled (VMT) and vehicle trips (VT). They can also reduce vehicle
exhaust emissions through relieving congestion. Our serious area PM-10
guidance requires that plans identifying on-road motor vehicles as a
significant sources must also evaluate the TCMs listed in section
108(f) of the CAA. Addendum at 42013.
In our review, we have primarily assessed the MAG plan's provisions
for implementing RACM and BACM and including MSM through TCMs based on
the measures' effectiveness in controlling directly-emitted PM-10 from
vehicle exhaust. We have not assessed the plan based on the TCMs'
potential benefit in controlling PM-10 precursors such as
NOX and SOX because (1) from available ambient
measurements, neither nitrates nor sulfates are important to overall
24-hour PM-10 concentrations in the Phoenix area (See EPA TSD section,
``BACT for Major Stationary Sources of PM-10 Precursors'' which shows
that total
[[Page 50260]]
secondary particulates from all sources have a maximum impact of 9.2
µg/m\3\ in 1995) and (2) Arizona has already targeted mobile
source NOX and SOX through an aggressive set of
mobile source controls which we believe cover the implementation of
RACM and BACM and inclusion of MSM requirements for tailpipe
NOX and SOX. See discussion immediately above on
technology controls for on-road motor vehicle exhaust.
In total, the MAG plan identifies 19 TCMs for consideration,
including the CAA section 108(f) measures. The plan does not identify
any potential most stringent TCMs from other areas. See EPA TSD section
``Implementation of BACM and MSM for On-Road Motor Vehicle Exhaust and
Paved Road Dust (TCMs).'' We believe that this list is complete and
propose to find that the MAG plan evaluates a comprehensive set of
potential TCMs for on-road motor vehicle exhaust emissions and the
potential MSM from other States.
Arizona has a long history of adopting and then enhancing programs
to reduce emissions from on-road motor vehicles by reducing VMT, VT,
and/or congestion.\18\ The area has an employer trip reduction
ordinance which applies to employers of 50 or more, a public outreach
program to encourage people to reduce driving, programs to improve
bicycling and pedestrian travel, and an extensive program to
synchronize traffic lights. In most instances, these programs were
adopted and implemented as part of carbon monoxide and ozone control
programs, but they also reduce PM-10.
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\18\ These plans include the MAG moderate and serious area
carbon monoxide plans and MAG moderate area ozone plan.
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With the additional measures in the MAG plan (including additional
traffic light synchronization, transit improvements, and bicycle and
pedestrian facility improvements), the overall TCM program is
strengthened and goes beyond the existing program. See EPA TSD, Table
TCM-3 in section ``Implementation of BACM and MSM for On-Road Motor
Vehicle Exhaust and Paved Road Dust (TCMs).'' Both strengthening and
expanding existing programs are key criteria for demonstrating the
implementation of BACM. See Addendum at 42013. Where the MAG plan has
rejected potential BACM, it provides a reasoned and acceptable
justification for the rejection.
All the adopted TCM BACM were implemented by June 10, 2000, the
BACM implementation date for the Phoenix area, or have on-going
implementation schedules because they are part of an on-going capital
improvement program (e.g., signal synchronization).
We propose to find that the combination of on-road motor vehicle
technology controls (described in the previous section) and TCMs in the
MAG plan provides for the implementation of RACM and BACM and inclusion
of MSM for on-road motor vehicle exhaust. We also propose to find that
the combination of TCMs and paved road dust measures (described in the
paved road section later in this preamble) provides for the
implementation of RACM and BACM and the inclusion of MSM for paved road
dust.
c. Nonroad Engines
The nonroad engine category covers a diverse collection of engines,
equipment and vehicles fueled by gasoline, diesel, electric, natural
gas, and other alternative fuels, including outdoor power equipment,
recreational equipment, farm equipment, construction equipment, lawn
and garden equipment, and marine vessels.
The suggested measures for controlling emissions from nonroad
engines fall into one of four categories: new emission standards,
programs to accelerate fleet turnover, programs affecting usage, or
fuels. In total, the MAG plan evaluates 8 measures in addition to clean
fuels measures for reducing PM-10 emissions from nonroad engines. We
believe that this list is complete and propose to find that the MAG
plan evaluates a comprehensive set of potential measures for nonroad
engines including the potential most stringent measures from other
States.
We have adopted national emission standards for a broad range of
nonroad engines. We consider that these standards, which apply to
nonroad engines sold in Arizona constitute at minimum a RACM-level
program for controlling emissions from nonroad engines. The CAA
preempts all states, except for California, from setting independent
nonroad emission standards. CAA section 209(e). Other states, however,
may adopt regulations identical to California's regulations, provided
they notify us and give appropriate lead time, 2 years, for
implementation. CAA section 209(e)(2)(B).
Arizona legislation allows ADEQ to adopt certain California nonroad
engine standards. MAG plan, p. 7-42. ADEQ originally committed to adopt
these California nonroad standards; however, subsequently, we adopted
federal nonroad engine standards that will achieve essentially the same
PM-10 reductions in the Phoenix area that adoption of the California
ones would. As a result, Arizona determined that adoption of the
California standards would not justify the resources ADEQ would need to
expend to adopt, implement, and enforce them and has now withdrawn its
commitment. See letter, Jacqueline E. Schafer, ADEQ, to Laura Yoshii,
EPA, ``Justification for not implementing CARB Off-road engine
standards for the Maricopa County PM-10 SIP,'' September 7, 2001
(``ADEQ Off-Road Letter'').
Arizona has adopted and implemented a year-round Cleaner Burning
gasoline program and limits on the sulfur content of diesel fuels. With
the addition of these measures, the overall nonroad engine program is
strengthened and goes beyond the existing federal program. See EPA TSD
section ``Implementation of BACM and Inclusion of MSM for Nonroad
Engines.'' Both strengthening and expanding existing programs are key
criteria for demonstrating the implementation of BACM. See Addendum at
42013. Where the MAG plan has rejected potential BACM, it provides a
reasoned justification for the rejection.
The MAG plan identifies CARB diesel as a potential MSM for nonroad
engines but does not adopt it. MAG plan, Table 10-7. The plan
identifies this measure as a potential MSM. MAG plan, Table 10-7. The
MAG plan claims that the measure is unreasonable on a cost basis. MAG
plan, p. 9-46.
Based on information in the Microscale plan, emissions from nonroad
engines are not implicated in 24-hour exceedances in the Phoenix area.
Microscale plan, pp. 17-19. All currently available evidence is that
24-hour exceedances are caused by local fugitive dust sources and
controls on these sources alone will result in the earliest practicable
date for attainment of the 24-hour PM-10 standard in the Phoenix area.
Microscale plan, pp. 17-19. Because implementation of CARB diesel would
not result in earlier attainment and thus unnecessary for expeditious
attainment, we propose to find that the MAG plan provides for the
inclusion of MSM to our satisfaction absent the adoption and
implementation of CARB diesel.
We, therefore, propose to find that MAG plan provides for the
implementation of RACM and BACM and inclusion of MSM for nonroad
engines.
d. Paved Road Dust
Paved road dust is the largest source of PM-10 in the Maricopa
area. It is fugitive dust that is deposited on a
[[Page 50261]]
paved roadway and then is re-entrained into the air by the action of
tires grinding on the roadway. Dust is deposited on the roadway from
being blown onto the road from disturbed areas; tracked onto the road
from unpaved shoulders, unpaved roads, or other unpaved access points;
stirred up from unpaved shoulders by wind currents created from traffic
movement; spilled onto the road by haul trucks; and carried onto the
road by water runoff or erosion.
The suggested measures for controlling emissions from paved road
dust fall into one of three categories: reductions in VMT and VT,
preventing deposition of material onto a roadway, and cleaning material
off the roadway. We have already discussed measures for reducing VMT
and VT in the section on TCMs above.
The MAG plan lists several potential BACM for paved road dust. It
also lists a number of potential MSM from other areas. We believe these
lists are complete and propose to find that the MAG plan evaluates a
comprehensive set of potential controls for paved road dust including
the potential MSM from other States.
Prior to the MAG plan, the cities and towns in the Phoenix area and
Maricopa County implemented a number of measures addressing paved road
dust. See MAG plan, Table 10-5. With the additional measures in the MAG
plan (described below), the overall control program to reduce paved
road dust is both strengthened and expanded beyond the existing
program. See EPA TSD section ``Implementation of BACM and Inclusion of
MSM for Paved Road Dust.'' Both strengthening and expanding existing
programs are key criteria for demonstrating the implementation of BACM.
See Addendum at 42013.
For the potential MSM, the MAG plan shows that these measures are
either adopted or are not in fact more stringent than existing Phoenix
area programs.
With the exception of the PM-10-efficient street sweepers measure
described below, all the adopted BACM for paved roads were implemented
by June 10, 2001, the BACM implementation deadline for the Phoenix
area, or have on-going implementation schedules because they are part
of an on-going capital improvement program, e.g., curbing. For the
reasons discussed below, we propose to find that the MAG plan provides
for the implementation of the PM-10 efficient street sweeper measures,
a MSM, as expeditiously as practicable, consistent with our proposed
MSM policy.
We, therefore, propose to find that the MAG plan provides for the
implementation of RACM and BACM and for the inclusion of MSM for paved
road dust.
Preventing Deposition of Material Onto a Roadway
Measures aimed at preventing track out on a paved road include
treating unpaved access points, preventing track out from construction/
industrial sites, treating shoulders on paved roads, controlling
emissions during material transport (e.g., truck covers, freeboard
requirements), and preventing erosion onto paved roads.
The MAG plan includes each of these measures.
Unpaved access points: In the MAG moderate area plan, local
jurisdictions focused on requiring new connections to public paved
streets to be paved. MAG plan, p. 9-74. In the serious area plan, the
focus has shifted to addressing existing unpaved access points in
addition to preventing new unpaved access points while maintaining the
previous programs. Most public entities committed to stabilize unpaved
access points when a connecting road is built, improved or
reconstructed. See, for example, Glendale Commitment, ``Reduce
Particulate Emissions from Unpaved Shoulders and Unpaved Access Points
on Paved Roads.'' Some cities have made explicit commitments for
stabilizing existing access points without this prerequisite, such as
Gilbert and Mesa. We also anticipate that routine city/town/County road
paving and stabilization projects will result in controlling a number
of existing unpaved access points. These projects combined with
increased enforcement of track-out restrictions and additional PM-10
efficient street sweeping efforts should reduce paved road emissions
attributable to unpaved access points.
The only potential MSM that the MAG plan identifies for unpaved
access points are track out control requirements for construction
sites. See MAG plan, Table 10-7. We discuss these measures in the next
section.
Track out. MCESD Rule 310, sections 308.2(c) and 308.3 address dirt
track out from construction/industrial sites requiring all work sites
that are five acres or larger and all work sites where 100 cubic yards
of bulk materials are hauled on-site or off-site each day to control
and prevent track out by installing a track out control device. The
rule also requires all work sites to clean up spillage or track out
immediately when it extends a cumulative distance of 50 linear feet or
more and, where track out extends less than 50 feet, to clean it up at
the end of the work day.
The MAG plan identifies, as a potential MSM for track out, South
Coast (Los Angeles area) Air Quality Management District's (South Coast
AQMD) Rule 403. MAG plan, Table 10-7. The plan concludes that the two
rules are reasonably similar in several respects, and where differences
exist, the relative impacts on control roughly balance each other out.
MSM Study, p. C-4.\19\ We agree. Both rules emphasize prevention and
rapid removal of track out. See EPA TSD section ``Implementation of
BACM and Inclusion of MSM for Paved Roads Dust,'' Note 2.
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\19\ The ``MSM Study'' is the ``Most Strigent PM-10 Control
Measure Analysis,'' Sierrra Research, May 13, 1998 found in Appendix
C, Exhibit 4 of the MAG plan.
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Unpaved Road Shoulders. As with unpaved access points, the MAG plan
demonstrates a shift to dealing with existing unpaved shoulders from
simply preventing new ones. MAG plan, Table 9-11. Maricopa County has
committed to treat 100 miles of shoulders along existing paved arterial
and collector roadways with high volume truck traffic by 2003, in
addition to its annual capital improvement projects for paving or
treating unpaved shoulders. Maricopa County commitment, 1999 revised
measure 5. Other jurisdictions have also made commitments to treat
shoulders. The commitments are set depending on the resources available
to each jurisdiction to implement them.
A.R.S. 9-500.04(3) and 49-474.01(4), adopted by the State
legislature in 1998, require the cities, towns and County of Maricopa
to develop and implement plans to stabilize targeted unpaved roads and
alleys and to stabilize unpaved shoulders on targeted arterials
beginning January 1, 2000. Although this legislation does not specify
how many shoulder miles to be controlled, we believe that the local
jurisdictions' efforts to meet this new legislation will result in the
control of unpaved shoulders where it is most needed.
Material Transport. Requirements for the control of PM-10 emissions
during material transport are found in MCESD Rule 310, sections 308.1
and 308.2. When hauling material off-site onto paved public roadways,
sources are required to: 1) load trucks such that the freeboard is not
less than three inches; 2) prevent spillage; 3) cover trucks with a
tarp or suitable enclosure; and 4) clean or cover the interior cargo
compartment before leaving a site with an empty truck.
The MAG plan identifies requirements for bulk material transport
[[Page 50262]]
in Imperial County (California) Regulation VIII as a potential MSM. MAG
plan, Table 10-7. The plan concludes that MCESD's rule is equally
stringent. We agree because Rule 310's requirements for bulk material
transport/hauling are essentially the same as Imperial County's
requirements.
Cleaning Material Off the Roadway
Measures for cleaning material off roadways are track out, erosion,
and spill removal requirements and road sweeping.
The MAG plan includes each of these measures:
Material spillage, erosion, or accumulation. MCESD Rule 310,
section 308.2 and 308.3 address rapid clean up of track out from
construction/industrial sites. Rule 310.01, section 306 requires
property owners/operators to remediate erosion-caused deposits of bulk
materials onto paved surfaces. Erosion-caused deposits are to be
removed within 24 hours of their identification or prior to resumption
of traffic on the pavement.
The MAG plan identifies South Coast AQMD's Rule 1186 and Mojave
Desert (San Bernadino, California) AQMD's Rule 403 as potential MSMs
for material spillage, erosion, and accumulation onto roadways. MAG
plan, Table 10-7. In both cases, the plan concludes that MCESD's rules
are more stringent. We agree. MCESD's rules require the clean up of
more incidences of spillage, etc. than does either the South Coast or
Mojave Desert rule. See EPA TSD, ``Implementation of BACM and Inclusion
of MSM for Paved Roads,'' Note 5.
Street sweeping. Most cities/towns and the County have on-going
street sweeping programs with variable sweeping frequencies. With some
exceptions, public entities implementing this measure have not
explicitly committed to increase their existing sweeping frequencies.
Phoenix, for example, approved a program in 1996 to increase the
frequency of residential street sweeping to match the uncontained trash
pick-up schedule. Phoenix commitment, measure 97-DC-5. However,
sweeping frequency is appropriately evaluated in combination with other
paved road measures because the emission-reducing potential of
increased sweeping frequency is closely associated with other factors.
These factors include whether the sweepers currently in use are PM-10
efficient (such that the act of sweeping does not cause increased
emissions) and whether the public entity has identified roads that tend
to experience higher silt loadings where more frequent sweeping is
likely to make an appreciable difference in PM-10 emissions. Because
sweeping frequency is among the criteria included in MAG's PM-10
efficient street sweeper solicitation (see below), we believe this
measure is largely incorporated into MAG's new program.
The MAG plan identifies as a MSM the PM-10 efficient street
sweeping provisions in South Coast Rule 1186. MAG plan, Table 10-7.
However, the plan's analysis pre-dates MAG's commitment for the
purchase and distribution of PM-10 efficient street sweepers and is no
longer current.
The MAG plan includes commitments by MAG, cities, towns and the
County for the purchase and use of PM-10 efficient street sweepers.
This commitment involves the allocation of $3.8 million in Congestion
Mitigation and Air Quality (CMAQ)\20\ funds for the FY 2000-2004
Transportation Improvement Program (TIP) to purchase PM-10 certified
street sweepers for the local jurisdictions to use. MAG has recommended
an additional $1.9 million in CMAQ funds be allocated to purchase PM-10
certified street sweepers in the FY 2001-2005 TIP. See MAG commitment,
``PM-10 Efficient Street Sweepers.''
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\20\ CMAQ funds are federal transportation funds awarded to
certain nonattainment areas for congestion management of air
quality-transportation projects such as paving unpaved roads.
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The funds allocated by MAG for this program should be sufficient to
replace approximately two-thirds of the 72 existing city/town/County
street sweepers.\21\ Each fiscal year in which CMAQ funds are allocated
for street sweepers, MAG will solicit requests for funding from cities,
towns and the County in the PM-10 nonattainment area. Funding requests
must identify by facility type (i.e. freeway, arterial/collector,
local) the number of centerline miles to be swept with the PM-10
certified units, expected frequency of sweeping, and average daily
traffic (if available).\22\ MAG will use this information to estimate
the emission reductions associated with each sweeper request and rank
the requests in priority order of effectiveness for consideration in
the allocation of CMAQ funds. See MAG commitment, ``PM-10 Efficient
Street Sweepers.''
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\21\ Some street sweepers may be additions to, as opposed to
replacements of, existing equipment.
\22\ See MAG, ``Methodology for Evaluating Congestion Mitigation
and Air Quality Improvement Projects,'' Draft Revised, June 21,
2001, pp. 18-22.
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In evaluating this program, we considered not only the number of
PM-10 efficient street sweepers to be purchased and distributed, but
whether the program incorporates use factors that influence emissions
reductions. The greatest emissions reduction benefit for this
mitigative measure will be achieved if the sweepers are used on a
frequent basis on-roads with high silt loadings or significant visible
accumulations.
Each public entity has a monetary incentive to compete for the PM-
10 efficient street sweepers, as the program is funded by MAG with a
low cost share (5.7 percent) requirement. Also, the new street sweepers
will either replace existing city-owned street sweeping equipment or
contracted out services, or be added to existing street sweeper
equipment/services. MAG's selection process includes PM-10 emissions
reduction potential, based on the types of roads each jurisdiction is
targeting for sweeping and how frequently they will be swept. This data
will assist MAG in distributing the street sweepers to local
jurisdictions in a way that maximizes the regional air quality benefits
of the program. In addition, when the cities/towns/County are awarded
PM-10 efficient street sweepers, their submittals will incorporate use
factors that maximize emission reductions from this measure.
We believe that implementation of the PM-10 efficient street
sweeper program will be implemented as expeditious as practicable. The
funding necessary to purchase this equipment is available only over the
course of several fiscal years and the purchase of the PM-10 efficient
street sweepers can only proceed at the rate these funds become
available.
South Coast's Rule 1186 requires any government or government
agency which contracts to acquire street sweeping equipment or services
for routine street sweeping on public roads that it owns and/or
maintains, where the contract date or purchase or lease date is January
1, 2000 or later, to acquire or use only certified street sweeping
equipment. The rule establishes street sweeper testing and
certification procedures. Unlike Maricopa's strategy, Rule 1186
requires that PM-10 efficient street sweepers be used whenever street
sweeping is contracted out as of January 2000, and it requires public
agencies to replace their existing street sweeping equipment with PM-10
efficient equipment only as they replace existing equipment.
MAG's PM-10 efficient street sweeper program is being funded over
the next 4 to 5 fiscal years, which may result in a greater number of
street sweepers being purchased and placed in
[[Page 50263]]
operation in a shorter time frame than could be expected using South
Coast's natural attrition approach. While it is possible that some
cities/towns in Maricopa may continue to contract out for street
sweeping services where PM-10 efficient sweepers may not be used, most
do not contract for street sweeping. Furthermore, due to the fact that
public entities will be competing for PM-10 efficient street sweepers
funded by CMAQ dollars with only a low cost share requirement, we
believe that the already limited reliance on contracted out services in
Maricopa County will be reduced as new PM-10 efficient equipment
becomes available and that contractors will switch to PM-10 efficient
equipment to meet new demand. In addition, MAG's program ensures that
the cities/town/County develop plans for how the street sweepers will
be used to maximize their emissions reduction potential. We, therefore,
believe that overall the Maricopa program is equivalent to South
Coast's Rule 1186.
e. Unpaved Parking Lots
This category includes emissions from re-entrained road dust from
vehicle traffic on unpaved parking lots and windblown dust entrained
from the disturbed surface of unpaved parking lots.
There are two principal ways to control emissions from unpaved
parking lots: prohibit unpaved parking lots or treat existing lots. MAG
plan identified both: a prohibition on unpaved haul road and parking or
staging areas and surface treatment to reduce dust from unpaved
driveways and parking lots. MAG plan, Table 5-2. The MAG plan
identified one potential MSM, South Coast's Rule 403 which controls
fugitive dust from parking areas on construction sites. MSM Study, p.
C-9 and 10. It did not identify any potential MSM for non-construction
site unpaved parking lots. We believe this list is complete and propose
to find that the MAG plan evaluates a comprehensive set of potential
BACM and MSM for unpaved parking lots.
Most local jurisdictions in Maricopa County identified ordinances
that require paving of new parking lots. In addition, MCESD Rule
310.01, section 303 requires owners/operators of an unpaved parking lot
larger than 5,000 square feet to pave, apply dust suppressants, or
apply gravel, according to the applicable rule's standards/test
methods. Applicable standards include a 20 percent opacity standard,
and an 8 percent silt content standard and/or a 0.33 oz/square foot
silt loading standard. Section 303.2. MCESD Rule 310, section 302.1
applies the same stabilization requirements to parking lots on
permitted facilities. Finally, many cities/towns have treated their own
parking lots or required treatment of private lots below MCESD's
thresholds.
In determining whether the MAG plan provides for the implementation
of BACM for unpaved parking lots, we are first specifically considering
whether the plan provides for the implementation of RACM for these
sources.\23\ In our 1998 moderate area PM-10 FIP for the Phoenix area,
we promulgated a RACM fugitive dust rule applicable to unpaved parking
lots in the Phoenix PM-10 nonattainment area. 40 CFR 52.128(d)(3). This
rule provides a starting point for determining whether the MAG plan's
measures for unpaved parking lots meet RACM. It is not necessary for
them to be identical to the FIP rule in order to meet the CAA's RACM
requirement, but only that they provide for the implementation of RACM.
However, if the submitted measures for a particular source are
identical to the FIP rule, we can determine without further analysis
that the MAG plan has provided for RACM for that source.
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\23\ While a serious area PM-10 plan must provide for both the
implementation of RACM (to the extent that it has not already
satisfied the requirement in its moderate area plan) and BACM, in
determining whether such a plan provides for BACM implementation, we
do not normally conduct a separate evaluation to determine if the
measures also meet the RACM requirements of the CAA as interpreted
by EPA in its General Preamble. See 57 FR 13540. This is because in
our serious area guidance (Addendum at 42010), we interpret the BACM
requirement as generally subsuming the RACM requirement (i.e., if we
determine that the measures are indeed the ``best available,'' we
have necessarily concluded that they are ``reasonably available'').
See Addendum at 42012-42014. Therefore, a separate analysis to
determine if the measures also represent a RACM-level of control is
not generally necessary. However, in this particular case, we have
already established through our FIP rule what we consider to be a
RACM-level of control for this source category. Thus our FIP rule
provides us with a baseline against which we can review whether the
MAG plan provides not only for RACM but also goes beyond that for
BACM. We also intend to eventually withdraw the FIP rule in favor of
local controls. In order to do this, we must determine under CAA
section 110(1), that, among other things, withdrawing the FIP rule
does not interfere with the RACM requirements in the CAA. An
explicit determination now simplifies this future action.
---------------------------------------------------------------------------
MCESD requirements for unpaved parking lots found in Rule 310.01,
section 303 are the same in terms of source coverage and applicable
standards/test methods for unpaved parking lots as the FIP rule, with
the only difference being that Rule 310.01 applies county-wide while
the FIP rule applies strictly to sources located in the PM-10
nonattainment area (located in the eastern third of the County). Rule
310.01 requirements became effective when the rule was adopted on
February 2000. In light of the fact that Rule 310.01 requirements are
the same as the FIP rule requirements and MCESD has made enforceable
commitments to improve compliance and enforcement of Rule 310.01, we
propose that the MAG plan provides for the implementation of RACM.
Given the additional city/town commitments in the MAG plan that
collectively increase the stringency of control on unpaved parking
lots, we propose that the MAG plan also provides for the implementation
of BACM. Both Rule 310.01 and the city/town commitments were
implemented prior to June 10, 2000, the BACM implementation deadline
for the Phoenix area.
As the only potential MSM, the MAG plan identifies South Coast's
Rule 403 which requires sources to apply dust suppressants to stabilize
at least 80 percent of unstabilized surface area and to comply with a 0
percent opacity property line limit. The MAG plan deems the respective
requirements roughly equivalent to Rule 310. MAG plan, p. 10-29. We
believe that the addition of a silt loading/content standard for
unpaved parking lots for sources covered under Rule 310 increases the
rule's stringency such that it is at least equivalent to that of South
Coast Rule 403. We, therefore, propose to find that the MAG plan
correctly concludes that there are no MSM in other State plans or used
in practice elsewhere that are applicable to the Phoenix area.
f. Disturbed Vacant Lands
This category includes windblown fugitive dust emissions from
disturbed surfaces of vacant lands. On vacant land, fugitive dust
emissions are caused by virtually any activity which disturbs an
otherwise naturally stable parcel of land, including earth-moving
activities, material dumping, weed abatement, and vehicle traffic. 63
FR 15919, 15937 (April 1, 1998).
The MAG plan includes three suggested measures for controlling
fugitive dust from vacant disturbed lands. MAG plan, Table 5-2. The
plan also identified controls on weed abatement operations and off-road
racing as potential MSM. MAG plan, Table 10-7. We believe this list is
complete and propose to find that the MAG plan evaluates a
comprehensive set of potential BACM and MSM for disturbed vacant lands.
Both MCESD rules 301 and 301.01 address vacant lots. Rule 310
requirements apply to vacant lots
[[Page 50264]]
located at permitted facilities (including construction sites) and Rule
310.01 requirements apply to nonpermitted sources.\24\ Rule 310 and
Rule 310.01 requirements apply to both publicly and privately owned
lots. Rule 310, section 302.3 and Rule 310.01, section 301 and 302.
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\24\ Permitted sources include any facility permitted by MCESD
and are not limited solely to those facilities with earthmoving
permits, Rule 310, section 102.
---------------------------------------------------------------------------
In determining whether the MAG plan provides for the implementation
of BACM for disturbed vacant land, we are also specifically considering
whether the plan provides for the implementation of RACM for this
source category. See Footnote 23. In our FIP, we promulgated a RACM
fugitive dust rule applicable to disturbed vacant land in the Phoenix
PM-10 nonattainment area. 40 CFR 52.128(d)(3). This rule provides a
starting point for determining whether the MAG plan's measures for
disturbed vacant lands meet the RACM requirement. It is not necessary
for them to be identical to the FIP rule in order to meet the CAA's
RACM requirement, but only that they provide for implementation of
RACM. However, if the submitted measures for a particular source are
identical to the FIP rule, we can determine without further analysis
that the MAG plan has provided for RACM for that source.
Rule 310.01 requirements for vacant lots and open areas are
virtually identical to the Phoenix FIP rule's requirements for these
sources. Rule 310.01, however, is more broadly applicable. It covers
vacant lots and open areas located anywhere in Maricopa County, in
contrast to the Phoenix FIP rule, which only applies to lots in the
Maricopa County portion of PM-10 nonattainment area. Rule 310.01,
sections 301 and 302. Unlike the FIP rule, Rule 310.01 also applies to
partially developed residential, industrial, institutional,
governmental, or commercial lots in Maricopa County, and any tract of
land in the Maricopa County portion of the nonattainment area adjoining
agricultural property. Rule 310.01, section 211.
Rule 310 requirements for vacant lots and open areas on permitted
sources are more stringent than those in Rule 310.01, in that Rule 310
requires stabilization of all inactive disturbed surface areas on
permitted facilities, regardless of their size. Rule 310, section
302.3. Rule 310 also contains requirements for weed abatement that
closely resemble the Phoenix FIP rule's weed abatement requirements,
except that Rule 310's threshold for coverage is lower.\25\
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\25\ Rule 310 requires any earthmoving operation that disturbs
0.1 acre or more to have a dust control plan, including weed
abatement by discing or blading, whereas the Phoenix FIP rule weed
abatement requirements only apply to disturbances equal to or
greater than 0.5 acres. Rule 310, section 303 and 40 CFR
52.129(c)(3) and (d)(3)(i).
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Vacant lots and open areas subject to Rule 310 and Rule 310.01 are
required to meet the same surface stabilization standards/test methods
as required in the Phoenix FIP rule.
In addition to requirements in Rule 310 and Rule 310.01, the MAG
plan contains commitments by several cities and towns to address vacant
disturbed lots. For example, seven jurisdictions require or will
require stabilization of disturbed vacant lots after 15 days of
inactivity (as compared to Rule 310.01's 60-day compliance period); two
(2) prohibit dumping of materials on vacant land; and two (2) will
stabilize all city-owned vacant lots. See EPA TSD section
``Implementation of BACM and Inclusion of MSM for Disturbed Vacant
Land.''
Because Rules 310 and 310.01 requirements are at least as stringent
as the FIP rule requirements and MCESD has committed to improve
compliance and enforcement of these rules (as discussed below), we
propose that the MAG plan provides for the implementation of RACM on
disturbed vacant land. Because these rules increase the number of lots
subject to control which collectively increase the stringency of
control on vacant disturbed lands, we propose that the MAG plan also
provides for the implementation of BACM. All measures for vacant
disturbed lands were implemented prior to the June 10, 2000 BACM
implementation deadline for the Phoenix area.
For its MSM analysis, the MAG plan identifies measures in Clark
County (Las Vegas, Nevada) Rule 41 and South Coast Rule 403. See MSM
Study, pp. C-11 and C-16, 17. The plan concludes that neither measure
is more stringent than the Maricopa measures because Rule 310 and
310.01 contain similar and equally or more stringent requirements. We
agree that the MCESD's rules are equally or more stringent.
We, therefore, propose to find that the MAG plan correctly
concluded that there are no MSM in other State plans or used in
practice elsewhere that are applicable to the Phoenix area.
g. Unpaved Roads
This category includes re-entrained dust from vehicle travel on
unpaved roads. There are three classes of unpaved roads in the Maricopa
nonattainment area: public roads, private roads that are publicly
maintained (also referred to as minimally-maintained or courtesy
grade), and private roads that are privately maintained.
The MAG plan includes three suggested measures for controlling
fugitive dust from unpaved roads: Surface treatment to reduce dust from
unpaved roads and alleys, traffic reduction/speed control plans for
unpaved roads; and prohibition of unpaved haul roads. MAG plan, Table
5-2. The MAG plan does not identify any other State's measures that are
more stringent than the ones already in the plan. We believe this list
is complete and propose to find that the MAG plan evaluates a
comprehensive set of potential BACM and MSM for unpaved roads.
In determining whether the MAG plan provides for the implementation
of BACM for unpaved roads, we are also considering whether the Plan
provides for the implementation of RACM for these sources. See Footnote
23. In our FIP, we promulgated a RACM fugitive dust rule applicable to
unpaved roads in the Phoenix PM-10 nonattainment area. 40 CFR
52.128(d)(3). This rule provides a starting point for determining
whether the MAG plan's measures for unpaved roads meet the RACM
requirement. It is not necessary for them to be identical to the FIP
rule in order to meet the CAA's RACM requirement, but only that they
provide for implementation of RACM. However, if the submitted measures
for a particular source are identical to the FIP rule, we can determine
without further analysis that the MAG plan has provided for RACM for
that source.
As discussed below, we propose to find that the MAG plan provides
for the implementation of RACM and BACM and the inclusion of MSM for
unpaved roads.
Surface treatment to reduce dust from unpaved roads and alleys. The
principal control measure for public unpaved roads and alleys is Rule
310.01, section 304, which requires all publicly-owned unpaved roads
and alleys with 250 vehicles per day (VPD) or more to be stabilized by
June 10, 2000 and those with 150 vehicles per day or more to be
stabilized by June 10, 2004.
Several cities have commitments that go beyond the requirements of
Rule 310.01 for publicly-owned unpaved roads. For example, the City of
Phoenix committed to--and accomplished before June 10, 2000--paving all
80 miles of its publicly-owned unpaved roads regardless of the level of
vehicle travel. Phoenix Commitment, Measure 98-DC-
[[Page 50265]]
7. Other cities, such as Tempe and Gilbert, have very few remaining
miles of public unpaved roads/alleys. See Tempe Commitments, Measure
98-DC-7 and Gilbert Commitments, Measure 98-DC-7.
For private roads, Rule 310, section 308.6, requires that
easements, rights-of-way, and access roads for utilities (electricity,
natural gas, oil, water, and gas transmission) that receive 150 or more
VPD must be paved, chemically stabilized, or graveled in compliance
with the rule's standards.
Private unpaved roads are scattered throughout Maricopa County,
within both County and city jurisdictions. A survey performed for us of
unpaved roads in Maricopa County determined that the great majority of
identified unpaved road mileage consists of privately-owned roads that
receive minimal maintenance by the Maricopa County Department of
Transportation (MCDOT).\26\
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\26\ Pacific Environmental Service, ``Survey for Fugitive Dust
Emission Sources'', April 15, 1999.
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MAG and MCDOT have committed to pave County minimal maintenance
roads within the nonattainment area that currently exceed 150 VDT and
meet criteria to become public highways, using $22 million in CMAQ and
MCDOT funds. MAG Commitment; Maricopa County Commitment, 1999 Revised
Measure 17. This program will pave an estimated 60 miles of unpaved
roadways in fiscal years 2001-2003 which is approximately 20 percent of
the privately-owned, publicly-maintained County-jurisdiction roads and
account for 40 percent of all VMT on these roads. Maricopa County has
also committed to continue to evaluate other roads for funding when
traffic levels increase above 150 vehicle trips per day. Maricopa
County Commitment, 1999 Revised Measure 17. We interpret this
commitment to apply to any private roads within County jurisdiction,
whether they currently receive minimal maintenance or not.
As the County evaluates roads for paving, it may make exceptions to
its commitment to pave roads with vehicle trips that exceed 150 VDT.
The County's evaluation process takes into account whether estimated
costs of paving are excessive (greater than $500,000 per mile).\27\
When MCDOT identifies a road that meets these criteria (i.e. the road
can be declared a public highway and costs are not excessive), it will
recommend that the Board of Supervisors open and declare the road a
public highway.\28\
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\27\ A private road begins to bear other than local traffic
through extensions of other nearby public roads or the construction
of an indirect source that attracts external drivers using the road
as a short cut. See Maricopa County Commitments, 1999 Revised
Measure 17.
\28\ Maricopa County provided an update to us of their efforts
to identify and pave County minimal maintenance roads. Kelly
McMullen, MCDOT, via email on May 4, 2001. The County identified
approximately 68 miles of minimal maintenance roads (courtesy
grading only) that potentially could have over 150 VPD traffic. Of
those roads, the County was unable to gather traffic count
information for approximately 3 miles due to repeated counter
vandalism or theft. The County included remaining roads with traffic
counts over 130 VPD (allowing for short term growth seasonal
variation, etc.) in its program to pave, totaling approximately 65
miles, consisting of approximately 186 segments. The first group of
these roads was expected to have a bid awarded in June 2001 and be
paved by Fall 2001. Design work for the second group was expected to
begin in Summer 2001 and is expected to go to bid for construction
within the next twelve months. Design work for the third group also
expected to begin in Summer 2001 and is expected to be bid
approximately 10-12 months following the second group. This third
group reflects the most difficult engineering and environmental
issues. Based on project engineer estimates at this time, the County
believes that six segments totaling approximately 3.0 miles may
exceed the reasonable cost threshold of $500,000 per mile, or have
issues with adjoining property owners that are not possible to
resolve within the SIP time frames. The County will evaluate whether
another method of dust suppression may be viable for those segments.
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Because BACM implementation properly takes costs into account, we
believe that MCDOT's criteria for selecting private roads to pave are
suitable in the context of a strategy to implement BACM and will result
in control of the great majority of high traffic unpaved roads.
Although available information on private roads in city jurisdictions
is limited, our existing information suggests that a typical privately-
owned unpaved road has little traffic on it.\29\ As a result, we
believe that the vast majority of private unpaved roads do not need to
be controlled in order for us to determine that the MAG plan provides
for the implementation of BACM for unpaved roads for the 24-hour
standard.
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\29\ Through MAG, we requested additional information on private
unpaved roads from the cities of Chandler, Scottsdale, Gilbert,
Glendale, Mesa, Phoenix, Tempe, Peoria, Avondale, Carefree, Cave
Creek, El Mirage, Goodyear, and Surprise. Letter Colleen McKaughan,
EPA, to Lindy Bauer, MAG, March 21, 2001. All but three cities
responded to the survey. Five cities state that they currently have
no private unpaved roads with greater than 150 VPD. Three cities
indicate they do not believe there are private unpaved roads with
greater than 150 VPD in their jurisdictions. The remaining cities
either have a small number of private road miles identified with
greater than 150 VPD or make no statement regarding the number of
private road miles with greater than 150 VPD in their jurisdictions.
Letter Lindy Bauer, MAG, to Colleen McKaughan, EPA, June 29, 2001.
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Traffic reduction/speed control plans for unpaved roads. Some
jurisdictions committed to evaluate this measure. Two jurisdictions
committed to posting 15 mph speed limit signs on private and public
unpaved roads and access ways; one jurisdiction has posted 15 mph speed
limits in all alleys. See MAG plan, Table 10-9. Also, under Rule 310,
owners/operators of unpaved haul roads and utility roads who comply
with the rule by limiting vehicle trips to 20 per day, must also limit
vehicle speeds to 15 mph. While speed limit controls are only being
implemented to a limited extent, we believe the plan's measures to pave
or otherwise stabilize unpaved roads in the Phoenix PM-10 nonattainment
area establish the critical commitments for the implementation of RACM
and BACM because road stabilization ensures emission reductions whereas
speed limits may or may not be observed.
Prohibition of unpaved haul roads. Rule 310 requires that unpaved
haul roads meet both a 20 percent opacity standard and a silt content
or silt loading standard. Rule 310, section 302.2. We propose to find
that this requirement is sufficient for the implementation of BACM for
these roads. We believe requiring compliance with both of these
standards ensures that these roads will be stabilized.
Evaluation of unpaved road measures in other areas found none that
are more stringent than the measures for unpaved roads in the MAG plan.
MAG plan, Table 10-7. We agree and propose to find that there are no
other MSM for unpaved roads than are already included in the MAG plan.
Please see the TSD section ``Implementation of BACM and Inclusion
of MSM for Unpaved Roads'' for a more detailed discussion of our
proposed findings.
h. Construction Sites and Activities
Sources of fugitive dust emissions at construction sites include
land clearing, earthmoving, excavating, construction, demolition,
material handling, bulk material storage and/or transporting
operations, material track out or spillage onto paved roads (which we
have addressed in the paved road section), and vehicle use and movement
on site (e.g., the operation of any equipment on unpaved surfaces,
unpaved roads and unpaved parking areas). Windblown emissions from
disturbed areas on construction sites are also a source of PM-10.
Construction operations, which are mostly earthmoving, represent some
90 percent of the emissions in this source category.
The suggested measure in the MAG plan for controlling emissions
from construction sites are actually various means of improving
compliance with controls rather than new control requirements for
construction sites. See
[[Page 50266]]
MAG plan, Table 5-2. MCESD had already adopted controls for
construction sites in its fugitive dust rule, Rule 310. The plan also
identifies several potential MSM. See MAG plan, Table 10-7. We propose
to find that the MAG plan evaluates a comprehensive set of potential
controls for construction sites emissions including the potentially MSM
from other states.
Rule 310's requirements, effective on February 16, 2000, apply to
any source required to obtain a permit under Maricopa County rules,
which includes earthmoving operations of 0.10 acre or more \30\ and
sources subject to title V permits,\31\ non-title V permits, or general
permits. In addition to rule requirements for fugitive dust sources
located at any permitted source, Rule 310 requires that a Dust Control
Plan (DCP) be submitted for any earthmoving operations of 0.10 acre or
more, and that the DCP be approved prior to commencing any dust
generating operation. The rule's definition of a dust generating
operation includes any activity capable of generating fugitive dust
including land clearing, earthmoving, weed abatement by discing or
blading, excavating, construction, demolition, material handling,
storage and/or transporting operations, vehicle use and movement, the
operation of any outdoor equipment or unpaved parking lots.
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\30\ Earthmoving operations include cutting and filling,
grading, leveling, excavating, trenching, loading or unloading of
bulk materials, demolishing, blasting, drilling, adding to or
removing bulk materials from open storage piles, back filling, soil
mulching, landfill operations, or weed abatement by discing or
blading.
\31\ Title V permits are operating permits required by Title V
of the Clean Air Act for major stationary sources and certain other
stationary sources.
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For other permitted sources, Rule 310 requires that a DCP be
submitted and approved prior to commencing any routine dust generating
activity, defined as any dust generating operation which occurs more
than 4 times per year or lasts 30 cumulative days or more per year.\32\
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\32\ This is in addition to the requirement to submit a DCP for
any earthmoving operation that disturbs 0.10 acre or more even if
the operation is subject to Title V or other permitting
requirements.
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Specific Rule 310 requirements include:
a 20 percent opacity requirement for any dust generating
operation
wind event controls
implementation of controls before, after and while
conducting any dust generating operation, including weekends, after
work hours and holidays
required controls and standards for:
unpaved parking lots
unpaved haul/access roads
disturbed open areas and vacant lots
bulk material hauling
bulk material spillage, carry-out, erosion and track out
open storage piles
weed abatement by blading or discing
a requirement in dust control plans for at least one
primary and one contingency control for all fugitive dust sources; the
contingency measure is to be immediately implemented if the primary
control proves ineffective
In order to comply with the rule's 20 percent opacity standard and
dust control plan requirements for implementing primary and/or
contingency controls for earthmoving activities, sources need to apply
one or more controls, which in most cases includes applying water or
another dust suppressant before and during operations. Inactive
disturbed surfaces must be stabilized to meet at least one of the
rule's stabilization standards (e.g. visible crusting, 10 percent rock
cover, etc.). Unpaved roads and unpaved parking lots must also be
stabilized to meet both a 20 percent opacity standard and a silt
content/loading standard.\33\ Test methods associated with
stabilization and opacity standards are contained in Appendix C, which
was submitted with Rule 310.
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\33\ Unpaved roads must meet a 6 percent silt content standard
or, alternatively, a 0.33 oz/ft\2\ silt loading standard, while
unpaved parking lots must meet an 8 percent silt content standard
or, alternatively, a 0.33 oz/ft\2\ silt loading standard.
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The 1999 revisions to Rule 310 that have increased the rule's
stringency include the addition of specific work practice standards,
the addition of stabilization standards and test methods for unpaved
surfaces, and modifications to the opacity test method (adding an
alternative opacity test method for unpaved roads and unpaved parking
lots and modifying the opacity test method for other sources). We
believe that the new and/or revised standards/test methods provide for
a greater degree of control than under the previous SIP-approved
version of Rule 310.
In addition to these Rule 310 revisions, MCESD made three
enforceable commitments to further strengthen requirements for
construction sites in 1999. See Maricopa County Commitments, Revised
Measure 6. MCESD has recently revised these commitments and will take
the revisions to the Maricopa County Board of Supervisors in December,
2001 for formal adoption as enforceable commitments. See Letter, Al
Brown, MCESD to Jack Broadbent, EPA, September 13, 2001 (MCESD
commitment letter). The commitments are to:
1. Research and develop a standard(s) and test method(s) for earth
moving sources, designed to be enforceable and meet BACM requirements
as to stringency and the number of sources that it applies to. Revise
Rule 310 and/or Appendix C by no later than December 2002 to modify the
existing opacity standard/test method or add an additional opacity
standard(s)/test method(s), tailored to non-process fugitive dust
sources that create intermittent plumes. This commitment will be met in
its entirety only if the standard(s)/test method(s) is approved by EPA.
The County is also proposing to support and coordinate with Clark
County, Nevada in the ongoing research to develop fugitive dust test
methods through the appropriation of $25,000.
2. Part 1: Onsite Implementation of Dust Control Plan
Raise awareness of onsite project supervisors to acquire and read
approved site dust control plans thereby improving the implementation
of the dust control plan at the construction site. This objective will
be achieved through one-on-one contact at the time of inspection and
through the development of a revised training curriculum and supporting
materials for both a classroom setting and onsite aids for improved
project management. Maricopa County inspectors will continue to go over
dust control plans with construction site personnel during the initial
site inspection and whenever issues arise during subsequent
inspections. The training curriculum being developed by the Arizona
Department of Transportation (ADOT) is scheduled for completion in
winter of 2002 and implementation of the second level of dust control
education will begin March--June 2003.
Part 2: Dust Control Plan Improvements
Research, develop and incorporate additional requirements for dust
suppression practices/equipment into dust control plans and/or Rule 310
by March--December 2002. Based on the ADOT research, MCESD research or
other alternative research, Maricopa County will develop a growing list
of criteria for effective versus ineffective dust suppression practices
that address various site circumstances.
3. Revise the sample daily recordkeeping logs for new and renewed
Rule 310 permits to be consistent with rule revisions and to provide
sufficient detail documenting the implementation of dust control
measures required by
[[Page 50267]]
Rule 310 and the dust control plan. Distribute sample log sheets with
issued permits and conduct outreach to sources by December 2001.
The first commitment addresses our concern that the existing
opacity standard and test method for earthmoving operations may not
always be sufficient to control construction site dust to BACM levels.
MCESD has already revised the opacity test method to deal partially
with this concern (see Rule 310, Appendix C), but we believe that
additional standards/test methods are needed to fully assure that
sources are effectively controlled.
Field research is needed to identify an appropriate standard(s) and
test method(s) to meet this commitment. MCESD originally committed to
complete this research and revise the opacity method by July 2001 but
was unable to do so. It now intends to work with Clark County which has
recently conducted research on test methods for earthmoving sources and
is planning to conduct a second phase of research. MCESD will
contribute funding to these efforts. MCESD has requested a one-year
extension of the deadline in its original commitment in order to
monitor, validate and verify the resulting test method(s) performance
in Maricopa County.
The second commitment addresses our concern that DCPs lack specific
criteria for dust suppressant application. For example, a source
engaged in grading or cut-and-fill earthmoving for a multi-acre project
may choose to comply with Rule 310 by applying water. However, neither
the rule nor DCPs establishes minimum criteria for the number of water
trucks/water application systems and water truck capacity for any given
size construction site or a ratio of earthmoving equipment to water
trucks. Also, for effective dust control, certain soil types may
require substantial pre-wetting, thorough mixing of water into the soil
for uniform penetration, and/or dust surfactant or tackifyer combined
with water; neither Rule 310 nor DCPs currently require such measures
for any sites.
Establishing criteria for dust control is complicated by variations
in soils, meteorological conditions, equipment size/use, project phase,
and level of activity. All these factors can impact the amount of water
(or other controls) needed to control fugitive dust on a particular
site on a particular day and has made it difficult to establish these
criteria. Because of this difficulty MCESD has revised its original
commitment to allow additional time to develop them.
MCESD has also expanded its original commitment to include a
program to work with on-site supervisors to assure that they obtain and
review the DCP for their sites. In implementing Rule 310 during the
last year, it found that site supervisors do not have or do not know
what is in their DCPs and thus may not be implementing appropriate dust
control methods.
The third commitment addresses our concern that while Rule 310
currently contains an acceptable recordkeeping requirement, a more
specific recordkeeping requirement would help improve compliance.
Currently neither the rule nor DCPs specify what information should be
included in a daily log. MCESD has revised its original commitment to
allow additional time to work with its stakeholders to develop daily
recordkeeping log sheets to provide sufficient detail documenting the
implementation of dust controls.
We propose to find that Rule 310 as adopted on February 16, 2000
and combined with the commitments by MCESD to make certain additional
changes to the Rule, provide for the implementation of RACM and BACM on
construction sites for the 24-hour PM-10 standards.\34\ We have also
determined that the revised commitments do not affect our previous
proposed finding that Rule 310 combined with the commitments provide
for the implementation of RACM and BACM on construction sites for the
annual standard. 65 FR 19964, 19980. The rule is comprehensive in scope
in that each dust source is subject to a set of requirements under Rule
310 (e.g. storage piles, dirt trackout, haul truck loads, disturbed
areas, earthmoving operations).
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\34\ These revised commitments are currently unenforceable
because they have not been adopted by Maricopa County's Board of
Supervisors. We are, however, proposing to approve these commitments
under CAA section 110(k)(3) as an enforceable element of the Arizona
SIP because we fully expect that the Board will adopt these
commitments as enforceable SIP commitments and the State will submit
them as a complete SIP revision prior to our final action. However,
if we do not receive the adopted commitments by the time we must
take final action, we propose to conditionally approve them under
CAA section 110(k)(4). If we take final action to conditionally
approve these commitments, MCESD will have one year to fulfill the
commitment or the approval will turn into a disapproval and we would
no longer be able to find that the MAG plan provides for the
implementation of BACM and the inclusion of MSM on construction
sites for either the annual or 24-hour standards.
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The MAG plan identifies several potential most stringent
construction site fugitive dust measures either in or under
consideration for inclusion in others SIPs. See MSM Study, Table 1-2
and Table 3-1.
Most of the potential MSMs are provisions in South Coast fugitive
dust rule, Rule 403. The MAG plan indicates that each of the South
Coast and MCESD's rules are more stringent than the other in certain
respects. MAG plan, p. 10-35. The MAG plan acknowledges that Rule 403
contains more stringent control measure requirements than those imposed
by Rule 310. For example, Rule 403 requires that water be applied to
soil not more than 15 minutes prior to moving the soil and requires
open storage piles to be watered twice per hour or covered. However,
the MAG plan indicates that Rule 310's 20 percent opacity limit is
generally more restrictive than Rule 403's property line standard
because a 20 percent opacity fugitive dust plume typically disperses to
zero visibility within 50 feet downwind of a source. MSM Study, p. C-
12. The MAG plan concludes that, on balance, Rule 310 is equally
stringent compared to Rule 403's construction site requirements. We
agree with this conclusion with the caveat that we believe Rule 310
and/or dust control plans require additional controls for dust
suppression. This caveat is addressed in the MAG plan's commitment to
research, develop and incorporate additional requirements for dust
suppression practices/equipment for construction activities into dust
control plans and/or Rule 310.
The MAG plan does not discuss any construction site measures from
other areas as potential most stringent measures. Based on our work
with the Las Vegas area, we have identified requirements in Clark
County Health District permits that are potentially more stringent than
Maricopa County's measures.\35\ These requirements include stand tanks
on projects that are 10 acres or more in size, an additional, separate
water truck when using a trencher or when screening, a separate water
truck or pull during landscaping, maintaining all stockpiles in a moist
condition, etc.
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\35\ These requirements are not in Clark County's fugitive dust
rule but rather are required practices in dust control permits.
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We propose to find that Rule 310's existing provisions and Maricopa
County's second commitment to research, develop and incorporate
additional requirements for dust suppression practices/equipment into
Rule 310 and/or DCPs are consistent with Clark County's requirements.
We have also identified a requirement in Imperial County Regulation
VIII that is potentially more stringent than Maricopa County's
measures. Imperial County Regulation VIII requires that water be
applied 15 minutes prior to
[[Page 50268]]
handling or transferring bulk material, chemical/physical
stabilization, or sheltering/enclosure of the operation and transfer
line. While Maricopa County Rule 310 requires owners/operators to
comply with a 20 percent opacity standard for any dust generating
operation and DCP must include a control measure for every fugitive
dust source (including bulk material handling/transfer), it does not
contain specific requirements as Imperial County does for this
activity. However, watering 15 minutes prior to handling may be overly
prescriptive and not necessary in all cases to meet the rule's
performance standards. We propose to find that Maricopa County's second
commitment to research, develop and incorporate additional requirements
for dust suppression practices/equipment into Rule 310 and/or DCPs is
consistent with Imperial County's requirements.
For these reasons, we propose to find that the MAG plan provides
for the inclusion of the MSM applicable to the Phoenix area for
construction sites and activities. See Footnote 34.
i. Agricultural Sources
The agriculture source category covers all dust generating
activities and sources on farms and ranches. These activities and
sources include land planning, tilling, harvesting, fallow fields,
prepared fields, field aprons, and unpaved roads. This source category
is a very significant contributor to 24-hour PM-10 standard exceedances
in the Phoenix area. At the West Chandler site, 55 percent of the
modeled exceedance was due to agricultural sources (a cotton field and
its apron). At the Gilbert site, 26 percent of the modeled exceedance
was due to an agricultural source (a field apron). See Microscale plan,
pp. 18-19.
In order to develop adequate controls for this source category,
Arizona passed legislation in 1997 establishing an Agricultural Best
Management Practices (BMP) Committee and directing the Committee to
adopt by rule by June 10, 2000, an agricultural general permit
specifying best management practices for reducing PM-10 from
agricultural activities. The legislation also required that the
implementation of agricultural controls begin with an education program
starting by June 10, 2000 with full implementation by December 31,
2001. See Arizona Revised Statutes (A.R.S.) 49-457.
After a series of meetings during 1999 and 2000, the Agricultural
BMP Committee adopted the agricultural general permit and associated
definitions, effective May 12, 2000, at Arizona Administrative Code
(AAC) R18-2-610, ``Definitions for R18-2-611,'' and 611, ``Agricultural
PM-10 General Permit; Maricopa PM10 Nonattainment Area'' (collectively,
general permit rule). The State submitted the general permit rule in
July 2000 and its analysis quantifying the emission reductions expected
from the rule and the demonstration that the rule meets the CAA's RACM,
BACM and MSM requirements in June 2001. We proposed to approve it as
meeting the CAA requirement for RACM on June 29, 2001 and signed the
approval on September 10, 2001. See 66 FR 34598.
The general permit rule requires a commercial farmer to implement
by December 31, 2001 at least one BMP for three categories of emission
sources on a farm: tillage and harvest, non-cropland, and cropland.
R18-2-610 defines commercial farmer as ``an individual, entity, or
joint operation in general control of 10 or more continuous acres of
land used for agricultural purposes within the boundary of the Maricopa
County PM10 nonattainment area.'' R18-2-610 defines tillage and harvest
as ``any mechanical practice that physically disturbs cropland or crops
on a commercial farm.'' R18-2-610 defines non-cropland as ``any
commercial farm land that: is no longer used for agricultural
production; is no longer suitable for production of crops; is subject
to a restrictive easement or contract that prohibits use for the
production of crops; or includes a private farm road, ditch, ditch
bank, equipment yard, storage yard, or well head.'' R18-2-610 defines
cropland as ``land on a commercial farm that: is within the time frame
of final harvest to plant emergence; has been tilled in a prior year
and is suitable for crop production, but is currently fallow; is a
turn-row.'' R18-2-610 defines a BMP as ``a technique verified by
scientific research, that on a case-by-case basis is practical,
economically feasible and effective in reducing PM-10 particulate
emissions from a regulated agricultural activity.''
For enforcement purposes, a commercial farmer is required to
maintain a record demonstrating compliance with the general permit. A
commercial farmer not in compliance with the general permit is subject
to a series of compliance actions described in A.R.S. 49-457.I-K.
The BMP Committee began implementing the general permit rule in
June 2000 by means of an extensive educational outreach program
informing growers about the BMPs. In addition, the BMP Committee
developed a Guide to Agricultural PM-10 Best Management Practices to
provide information and guidance on how to effectively implement
BMPs.\36\ Farmers must be in compliance with the general permit rule by
December 31, 2001.
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\36\ ``Guide to Agricultural PM-10 Best Management Practices,
Maricopa County, Arizona PM-10 Nonattainment Area,'' Governor's
Agricultural BMP Committee, First edition, February, 2001.
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For the reasons discussed below and more extensively in the section
``Implementation of BACM and Inclusion of MSM for Agricultural
Sources'' in the EPA TSD, we propose to find that the State's general
permit rule meets the CAA's requirements to provide for the
implementation of BACM by June 10, 2000 in CAA section 189(b)(1)(B) and
to include MSM in section 188(e). Our proposed finding is applicable to
both the annual and 24-hr standards. It revises our previously proposed
finding in the annual standard proposal that the State's commitment in
the MAG plan to adopt and implement agricultural best management
practices meets the CAA's requirements for BACM and MSM by substituting
the BMP general permit rule. 65 FR 19964, 19981.
In September 1998, the Agricultural BMP Committee appointed an Ad-
hoc Technical Group to develop a comprehensive list of potential BMPs
for regulated sources in the Maricopa County nonattainment area.
Participants on the Ad-hoc Group included the USDA NRCS, USDA
Agricultural Research Service, University of Arizona College of
Agriculture, ADEQ, University of Arizona College of Agriculture and
Cooperative Extension, Western Growers Association, Arizona Cotton
Growers Association, Arizona Farm Bureau Federation, and EPA. BMP TSD,
p. 15.
The Ad-hoc Technical Group reviewed available dust control
regulations, literature, and technical documents, and developed a list
of 65 conservation practices potentially suitable to agricultural
sources in the Maricopa County nonattainment area for further
consideration. BMP TSD, p. 16. These 65 measures represented a broad
spectrum of potential BMPs, many of which related to conservation
practices used in the western United States that had never been
evaluated in the context of reducing PM-10.
The Agricultural BMP Committee thoroughly reviewed the potential
practices presented by the Ad-hoc Technical Group and evaluated the
potential BMPs using available information on technological
feasibility, costs, and energy and environmental impacts. After an
analysis of the limited
[[Page 50269]]
information available and numerous public discussions, the Committee
decided to include 34 of the 65 BMPs in the general permit rule and
divided these 34 BMPs into the three categories of farm activities
specified in A.R.S. 49-457.N.: 10 BMPs applicable to the tillage and
harvest category; 10 BMPs applicable to the non-cropland category; and
14 BMPs applicable to the cropland category. See BMP TSD, 17. In
selecting these BMPs, the Committee deemed them to be feasible,
effective and common sense practices for the Phoenix area which
minimized potential negative impacts on local agriculture.
Of the 31 potential BMPs eliminated, the majority were dropped
because they either duplicated another BMP or did not reduce PM-10.
Other reasons for elimination included the impracticability of a BMP
for the Maricopa County Area, lack of cost effectiveness, or
infeasibility of implementation. See June 13, 2001 BMP submittal,
Enclosure 3, Attachment 8.
At the time the BMP Committee was developing the general permit
rule, there was very limited available information concerning the
technological feasibility, costs, and energy and environmental impacts
of these BMPs. Although the Committee determined that all the selected
BMPs were technologically feasible control requirements, it found that
calculating the other impacts on a commercial farmer was difficult.
Because of the variety, complexity, and uniqueness of farming
operations in Maricopa County, the Committee concluded that farmers
need a variety of BMPs in each of the three categories of agricultural
activities to choose from in order to tailor PM-10 controls to their
individual circumstances. Further, the BMP Committee acknowledged that
there is a limited amount of scientific information available
concerning the emission reduction and cost effectiveness of some BMPs,
especially in relation to Maricopa County. The BMP Committee balanced
the limited scientific cost effectiveness information with the common
sense recognition that the BMPs would reduce wind erosion and the
entrainment of agricultural soils, thereby reducing PM-10. As a result,
and given the myriad factors that affect farming operations, the BMP
Committee concluded that requiring more than one BMP for each of the
three agricultural categories could not be considered technically
justified and could cause an unnecessary economic burden to farmers.
Instead, the BMP Committee and ADEQ agreed to monitor the effectiveness
of the BMPs and adjust the program, if needed, in the future. BMP TSD,
p. 18.
The general permit rule, as finally adopted by the BMP Committee in
May 2000 as BACM and MSM, requires that commercial farmers implement at
least one BMP for the tillage and harvest, cropland, and non-cropland
categories by December 31, 2001.
We define a BACM-level of control to be, among other things, the
maximum degree of emission reduction achievable from a source or source
category which is determined on a case-by-case basis, considering
energy, economic and environmental impacts. Addendum at 42010. Based on
the BMP committee's findings regarding technological feasibility and
economic effects of requiring more than one BMP per category, we
believe that the BMP rule provides the maximum degree of emission
reductions achievable from the agriculture source category in the
Phoenix area and, therefore, meets the BACM requirement in section
189(b)(1)(B).\37\
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\37\ We also considered a BACM-level control as going beyond
existing RACM-level controls, such as expanding use of RACM (e.g.,
paving more miles of unpaved roads). Addendum at 42013. As noted
previously, we have proposed to approve the general permit rule as
meeting the RACM requirement in CAA section 189(a)(1)(C). 66 FR
34598. In that proposal, we stated our belief ``that the general
permit rule represents a comprehensive, sensible approach that
meets, and in fact far exceeds, the RACM requirements of CAA section
189(a)(1)(C) and EPA guidance interpreting those requirements.'' 66
FR 34598, 34602. Moreover, we explained that the State also intended
the general permit rule and its enabling legislation to meet the
CAA's serious area requirements. 66 FR 34598, 34599. Thus today's
proposal that the general permit rule meets the BACM and MSM
requirements of the Act is consistent with our prior action.
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A requirement that an individual source select one control method
from a list, but allowing the source to select which is most
appropriate for its situation, is a common and accepted practice for
the control of dust. For example, in its PM-10 FIP for Phoenix, we
promulgated a RACM rule applicable to, among other things, unpaved
parking lots, unpaved roads and vacant lots. The rule allows owners and
operators to choose one of several listed control methods (pave, apply
chemical stabilizers or apply gravel). 40 CFR 52.128(d). In the case of
the FIP, those subject to the fugitive dust rule were given a choice of
control methods in order to accommodate their financial
circumstances.\38\
Allowing sources the discretion to choose from a range of specified
options is particularly important for the agricultural sector because
of the variable nature of farming. As a technical matter, neither we
nor the State is in a position to dictate what precise control method
is appropriate for a given farm activity at a given time in a given
locale. The decision as to which control method from an array of
methods is appropriate is best left to the individual farmer. Moreover,
the economic circumstances of farmers vary considerably. As a result,
it is imperative that flexibility be built into any PM-10 control
measure for the agricultural source category whether that measure is
required to meet the RACM or BACM requirements of the Act.
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\38\ See, as examples, SCAQMD Rule 403 (providing for
alternative compliance mechanisms for the control of fugitive dust
from earthmoving, disturbed surface areas, unpaved roads etc.); and
SCAQMD Rule 1186 (requiring owners/operators of certain unpaved
roads the option to pave, chemically stabilize, or install signage,
speed bumps or maintain roadways to inhibit speeds greater than 15
mph). We proposed to approve these SCAQMD rules as meeting the RACM
and/or BACM requirements of the CAA on August 11, 1998 (63 FR 42786)
and took final action approving them on December 9, 1998 (63 FR
67784). See also the approval of Maricopa County Environmental
Services Department (MCESD) Rule 310 as meeting the RACM/BACM
requirements (62 FR 41856, August 4, 1997) and the proposal to
approve updated Rule 310 and MCESD Rule 310.01 as meeting the same
requirements (65 FR 19964, April 13, 2000).
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We believe that the work of the BMP Committee resulted in the
timely adoption of the general permit and educational programs that
requires BACM implementation on a schedule that will allow time for the
agricultural community to understand and select appropriate BMPs and to
transition to new practices, some of which may involve the purchase of
new equipment. Based on these factors, we believe that the BMP
implementation schedule is as expeditious as practicable and meets the
BACM implementation deadline for the Phoenix area of June 10, 2000.
The MAG plan identified two potentials MSM for agricultural sources
(1) cessation of tilling on high winds days in South Coast's Rule 403.1
and (2) soil erosion plans in South Coast's Rule 403. MAG plan, Table
10-8. The plan concluded that neither is, by itself, MSM for the
Phoenix area.
South Coast's 403.1, ``Wind Entrainment of Fugitive Dust,'' applies
only in the Coachella Valley (Palm Springs) portion of the South Coast
Air Basin and requires that, when wind speeds exceed 25 miles per hour
(mph), agricultural tilling and soil mulching activities should cease.
While the measure applies throughout the year, the high wind days tend
to occur during a high-wind season that extends between April and June.
The Coachella Valley typically experiences high winds on 47 days of the
year. MAG estimated that there were a total of 37 hours,
[[Page 50270]]
representing 11 days, with wind speeds greater than 15 mph in 1995 in
Maricopa County.
The BMP general permit rule includes ``limited activity during high
wind event'' as one of ten BMPs that a grower can choose for the
Tillage and Harvest category. According to an analysis in the MAG plan,
postponing tilling on high wind days would reduce emissions by 72
percent on high-wind days. MSM study, p. 4-23. However, because only 15
percent of the Maricopa County PM-10 nonattainment area tilling occurs
during the high wind season (March through September) and because less
than 4 percent of the days during this period experience winds greater
than 15 mph, the air quality benefits of the measure would be small
(i.e, 0.08 metric tons per average annual day in 1995) for the annual
standard. MSM study, p. 4-23. Emissions from tilling are a very small
contributor to total agricultural emissions on the 1995 design day
(which was a high-wind day), representing just 1.6 percent of all
agricultural emissions and are not implicated in 24-hour exceedances.
URS, Technical Support Document for Quantification of Agricultural Best
Management Practices, June 8, 2001 (Ag Quantification TSD), p. 3-11 and
Microscale plan, pp. 18-19. Moreover, based on the limited amount of
information available regarding the control efficiencies for the ten
BMPs in the Tillage and Harvest category, the control efficiency for
``limited activity during high-wind event'' is on average as effective
or less effective than the other BMPs in this category. Ag
Quantification TSD, pp. 2-8 to 2-10.
South Coast's Rule 403, ``Fugitive Dust,'' requires the
implementation of conservation practices to reduce PM-10 from
agricultural sources in the South Coast PM-10 nonattainment area. Under
Rule 403(h), agricultural operations exceeding 10 acres within the
South Coast Air Basin are exempt from the rule's requirements for
fugitive dust if the farmer implements the conservation practices in
the most recent Rule 403 Agricultural Handbook. See ``Rule 403
Agricultural Handbook: Measures to Reduce Dust from Agricultural
Operations in the South Coast Air Basin,'' South Coast AQMD, December
1998 (the Handbook). Because the requirements of Rule 403 are more
stringent than the requirements for conservation practices in the
Handbook, it is assumed that farmers will always choose to comply with
the latter's provisions. Thus the Handbook, rather than Rule 403
itself, is effectively the potential MSM.
For a variety of reasons, it is difficult to directly compare the
requirements in the general permit with the requirements in the
Handbook. First, the South Coast did not attempt to estimate the
reductions and cost from each conservation practice. Second, the types
of crops grown in Maricopa County and the South Coast area differ
significantly. For example, cotton is a dominant crop in Maricopa
County but is not grown in the South Coast Air Basin. Third, the
Handbook allows a grower to substitute a local ordinance for the three
conservation practices required for ``inactive'' agricultural land;
however, the minimum requirements for the local ordinance are not
specified. Handbook, section II, p.4. Fourth, the general permit rule
and the Handbook also differ in terms of exemption and waivers. The
general permit rule does not exempt any crop types or provide a waiver
option, but the Handbook exempts orchards, vine crops, nurseries, range
land, and irrigated pastures from requiring a practice for the active
and inactive categories. Finally, the Handbook also allows farmers to
request a waiver if the farmer cannot apply the required practices or a
verifiable alternative.
While the general permit rule divides agricultural activities into
three categories and the Handbook divides them into six, and the
terminology used is different, the categories of activities covered are
essentially coterminous. Cf. Handbook, section I and ACC R18-2-610.7,
.12, .22, .33. However, depending on the type of farming operation, the
general permit rule would require implementation of at least one BMP
for each of the Tillage and Harvest, Cropland, and Non-Cropland
categories and the Handbook requires from one to three practices for
its six agricultural categories.
As discussed above, in the BACM section of this TSD, the BMP
Committee concluded that, because of the variety, complexity, and
uniqueness of farming operations and because agricultural sources vary
by factors such as regional climate, soil type, growing season, crop
type, water availability, and relation to urban centers, agricultural
PM-10 strategies must be based on local factors. Therefore, the general
permit rule, as finally adopted by the BMP Committee in May 2000,
reflects the conclusion of the BMP Committee that farmers need a
variety of BMPs to choose from in order to tailor PM-10 controls to
their individual circumstances. Further, the BMP Committee acknowledged
that there is a limited amount of scientific information available
concerning the emission reduction and cost effectiveness of some BMPs,
especially in relation to Maricopa County. The BMP Committee balanced
these limitations with the common sense recognition that the BMPs would
reduce wind erosion and the entrainment of agricultural soils, thereby
reducing PM-10.
While the Committee surveyed measures adopted in other geographic
areas, these measures were of limited utility in determining what
measures are available for the Maricopa County area. Given the limited
scientific information available and the myriad factors that affect
farming operations, the BMP Committee concluded that requiring more
than one BMP could not be considered technically justified and could
cause an unnecessary economic burden to farmers.
Adding to concerns about the economic feasibility of requiring more
BMPs per farming activity is the general uncertainty regarding the cost
of the BMPs and continued viability of agriculture in Maricopa County.
Between 1987 and 1997, the number of farms operating in Maricopa County
declined by approximately 30 percent and the amount of land farmed
declined by approximately 50 percent. This trend is expected to
continue. Finally, in order to justify additional requirements for
farming operations in the area beyond those in the general permit rule,
the BMP Committee determined that a significant influx of money and
additional research would be needed. BMP TSD, p. 18.
Based on all of these factors, the BMP Committee concluded that the
Handbook's practices were neither technologically nor economically
feasible for agricultural sources in Maricopa County. BMP TSD, p. 18.
We agree with the analysis of the BMP Committee. As noted
previously, the development of the general permit rule was a multi-year
endeavor involving an array of agricultural experts familiar with
Maricopa County agriculture. Maricopa County is only the second area in
the country where formal regulation of PM-10 emissions from the
agricultural sector has ever been attempted. For the reasons discussed
above, we propose to conclude that the BMP general permit rule meets or
exceeds the stringency of South Coast Rule 403.1's requirement for
cessation of tilling during high winds. Based on the forgoing analysis
of the Handbook, we also propose to conclude that the Handbook's
requirements are neither technologically nor economically feasible for
Maricopa County. Because all the identified potential MSM have either
not been demonstrated to be more
[[Page 50271]]
stringent than existing Maricopa County controls or found to be
infeasible for the area, we propose to find that the MAG plan provides
for the inclusion of MSM as required by CAA section 188(e) to our
satisfaction.
j. Residential Wood Combustion
The residential wood combustion (RWC) category includes emissions
from the burning of solid fuel in residential fireplaces and woodstoves
as well as barbecues and firepits.
Measures to control PM-10 from residential woodburning include a
public education program, woodburning curtailment programs, retrofit
requirements and restrictions or bans on the installation of
woodburning stoves and/or fireplace. In total the MAG plan lists 11
potential BACM and 10 potential MSM. MAG plan Tables 5-2 and 1-7. We
believe these list are complete and propose to find that the MAG plan
evaluates a comprehensive set of residential woodburning measures.
MCESD Rule 318, Approval of Residential Woodburning Devices,
establishes standards for the approval of residential woodburning
devices that can be used during restricted-burn periods. Maricopa
County's Residential Woodburning Restriction Ordinance provides that
restricted-burn periods are declared by the Control Officer when the
Control Officer determines that air pollution levels could exceed the
CO standard and/or the PM standard (150 µg/m\3\). We approved
Rule 318 and an earlier version of the ordinance (revised April 21,
1999) as providing for the implementation of RACM. See 64 FR 60678
(November 8, 1999).
MCESD revised the ordinance on November 17, 1999 to allow the
Control Officer to declare restricted-burn periods when the particulate
matter pollution levels could exceed the ``particulate matter no-burn
standard'of 120 µg/m\3\. We proposed to approve the revised
ordinance as part of the annual standard proposal. 65 FR 19964, 19990.
In addition, A.R.S. section 9-500.16 and A.R.S. section 11-875 (1998)
required cities and the County to adopt by December 31, 1998, an
ordinance that prohibits the installation or construction of a
fireplace or wood stove unless it is a fireplace with a permanently
installed gas or electric log insert, a fireplace or wood stove that
meets EPA's Phase II wood stove requirements, or a fireplace with a
wood stove insert that meets EPA's Phase II stove requirements. Most
jurisdictions have adopted or have committed to or indicated that State
law requires them to adopt the required ordinance. See MAG Plan, pp, 7-
55 to 7-64.
With these additional controls, the overall residential woodburning
restriction program is strengthened and goes beyond the existing RACM-
level program. Both strengthening and expanding existing programs are
key criteria for demonstrating the implementation of BACM. See Addendum
at 42013. Where the MAG plan has rejected potential BACM, it provides a
reasoned justification for the rejection. All measures were implemented
by June 10, 2000, the BACM implementation deadline for the Phoenix
area. We, therefore, propose to find that the MAG plan provides for the
implementation BACM for residential wood combustion.
The MAG plan identified a number of potential MSM for residential
wood combustion. Except for the adoption of a lower threshold for
calling no burn episodes, the plan does not provide for the adoption of
any of these measures but provides reasoned and acceptable
justifications for their rejection. Therefore, we propose to find that
the MAG plan provides for the inclusion of MSM.
k. Secondary Ammonium Nitrate
Secondary ammonium nitrate is formed by a chemical reaction in the
atmosphere between oxides of nitrogen (NOX) and ammonia
(NH\3\). Ninety percent of NOX comes from motor vehicle
exhaust (both on and off road) and 99.9 percent of NH\3\ comes from
animal wastes. See MAG plan, Table 3-1.
Two potential BACM were identified for ammonia nitrate control:
reduce emissions of ammonia and nitrates from agricultural operations
and require animal waste management plans for farms/ranches with more
than 50 animals. The first measure involves tilling in of manure used
as fertilizer within 48 hours of application. MAG plan, Table 6-1,
measure 97-AG-3. The second measure would focus on reducing ammonia
emissions from livestock waste during the winter months when conditions
are most conducive to ammonium nitrate formation. MAG plan, Appendix B,
Exhibit 5, p. 5-70. For MSM, no measures were found that required
animal waste management plans for farms or ranches and no other
measures were identified. See MAG plan, Table 10-7. A large number of
measures that could reduce NOX emissions were identified and
have been evaluated for on-road motor vehicles and nonroad engines. We
believe this list of measures is complete and propose to find that the
MAG plan evaluates a comprehensive set of potential controls for
ammonium nitrate.
Data from earlier studies indicate that ammonia emissions would
need to be reduced by 80 percent to have an appreciable impact on
ambient concentrations of ammonium nitrate. MAG plan, Appendix B,
Exhibit 5, p. C-1. Essentially all ammonia emissions in the inventory
are from livestock and not from the application of manure to
agricultural fields. As result, controls on the application of manure
are very unlikely to have any impact on PM-10 levels in the Phoenix
area and therefore are not technologically feasible. \39\ The estimated
reduction in ammonia from implementing waste management plans is 30
percent, far short of the 80 percent needed to show impact on PM-10
levels (MAG plan, Appendix B, Exhibit 5, p. 5-72), so we also believe
that this measure is currently not technologically feasible.
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\39\ We consider a measure technologically feasible for an area
only if it has the potential to reduce emissions in a manner that
reduces ambient concentrations in the area.
---------------------------------------------------------------------------
Other than the on-road vehicle and nonroad engine categories, we do
not believe that there are any other sources of NOX that
should be called significant in terms of contributing to ammonium
nitrate levels. See MAG plan, Table 3-1.
Arizona has adopted a number of measures for controlling
NOX emissions from motor vehicles and nationally, we have
established emission standards for control of NOX from both
on- and nonroad engines. The MAG plan does not identify any
technologically feasible measures for the control of ammonia. For these
reasons, we propose to find that the MAG plan provides for the
implementation of RACM and BACM and for the inclusion of MSM for
secondary ammonium nitrates.
1. MCESD's Commitments to Improve Compliance and Enforcement of its
Fugitive Dust Rules
MCESD has committed to expanding and improving the compliance and
enforcement program for its fugitive dust rules. These enforceable
commitments are found in Maricopa County, 1999 Revised Measure 6,
adopted December 15, 1999. A narrative description of them and other
program changes are found in Appendix IV, Exhibit 3 to the MAG plan's
modeling TSD. MCESD has also committed to continuing to improve Rule
310 and Rule 310.01. These commitments are described in Section E.3.h.
``Construction Sites and Activities.''
[[Page 50272]]
These improvements to the compliance and enforcement programs
include increased public outreach and education, increased funding and
staffing, increased inspection frequency, revised enforcement policies,
and commitments to program evaluations and improvements. They address
many of the program areas that are key to improving compliance and we
believe form a solid program for increasing the effectiveness of the
County's fugitive dust program.
We review these enforceable commitments and their current status
below:
Staffing
Maricopa County committed to increasing its inspection staff to 8
inspectors, 1 supervisor, 1 aide and 2 enforcement officers by the end
of January 2000 and to add a coordinator to the Small Business
Environmental Assistance Program to assist smaller builders and
construction companies and to help develop and implement education
programs. It also committed to hire an attorney in the County
Attorney's office to expedite civil litigation and to assist with
prosecuting Class One Misdemeanor cases by April 2000. Total resources
devoted to the fugitive dust program were to be increased to 15
positions, a 25 percent increase over previous levels. After reaching
the committed staffing level, MCESD was to review the program in March
2000 to evaluate its effectiveness and the potential need to add more
staff.
By the end of January 2000, inspection unit staffing increased to 8
inspectors, 1 supervisor, 1 coordinator (to oversee permit issuance and
track notices of violations), 2 aides and 2 enforcement officer. By May
2000, the County Attorney's office hired an attorney, paralegal, and
support staff. In 2000, the Department found that the existing staff in
the Small Business Environmental Assistance Program was able to handle
the workload for assisting smaller builders and construction companies
and for helping to develop and implement education programs. MCESD will
re-evaluated the need for an additional coordinator in the small
business assistance program when the second generation outreach and
education materials are completed. In total, resources devoted to the
fugitive dust program during the past year were 17 positions, a 42
percent increase over previous levels.
Organization
MCESD created a new enforcement section under the direct
supervision of the MCESD Director/Air Pollution Control Officer (APCO).
This position streamlines enforcement by reducing senior management
review and approval of enforcement actions and allows enforcement
officers to submit directly to the APCO's desk all enforcement actions
requiring APCO approval.
In addition, MCESD committed to locate inspectors in two new
regional offices to provide quicker response times to dust-related
complaints and allow more time in the field. It has in fact located
inspectors in four regional offices.
Funding
For FY 1999-2000, revenue for fugitive dust program was projected
to be $1.12 million from annual earth moving permit fees, a $772,000
increase over the previous level. The increase was due to the 1998 fee
increase for earth moving permits.
For FY 2000-2001, anticipated revenue for the fugitive dust program
is approximately $1.7 million, generated from annual earth moving
permit fees. This is a $1.35 million increase over the previous level.
Inspection Program
MCESD committed to develop by April, 2000 inspection priorities for
vacant lots and unpaved parking lots that consider lot size and number
of sources, with larger lots being inspected first and smaller lots in
succeeding years. A number of cities have municipal programs to address
these sources; therefore, the Department committed to initially direct
its inspections to cities lacking such programs and to track the city
plans that are required by State statute to stabilize target unpaved
roads, alleys and unpaved shoulders.
Prior to its adopting additional commitments in December 1999,
MCESD had already increased inspection rates and improved procedures
for permitted sources such as construction sites including:
Proactively inspecting sites larger than 10 acres, 3 to 6
times per year and inspect smaller sites once within 30 days of project
start date.
Scheduling weekend inspections randomly once per month.
Providing a shortened complaint response time with a goal
of 8 hours for high priority complaints and maintaining the current
goal of 24 hours for others
Revising standard operating procedures and checklists for
fugitive dust inspections to be consistent with the revised rules.
Revising inspection standard operating procedures to have
inspectors check for records and inspect fugitive dust sources at
permitted stationary sources.
MCESD did develop by April, 2000 inspection priorities for vacant
lots and unpaved parking lots considering lot size and number of
sources with larger lots being inspected first and smaller lots in
succeeding years. EPA and MCESD initially attempted, but were
unsuccessful, to convert an Assessor's Office database of vacant lots
into a user-friendly format for identifying priority lots. Now, MCESD
inspectors are assigned geographical districts and are compiling notes
on the vacant lots and unpaved parking lots in each district during
their routine surveillance activities. Under current MCESD policy, the
inspectors are first directed to handle all complaints and then to
begin to address the larger sites on the individual district lists. In
2000, the inspectors made 499 inspections on vacant lots, unpaved
parking lots, and unpaved roads.
Enforcement Program
To meet its commitment to revise its enforcement program, MCESD
issued a revised air quality enforcement policy on April 28, 2000. See
Air Quality Violation Reporting and Enforcement Policy and Procedure,
MCESD, April 28, 2000. This policy:
Includes guidelines for initiating various enforcement
actions
Includes guidelines for reinspecting
Defines timely and appropriate action by laying out
guidelines for which type of violation is appropriate for specific
enforcement actions and for the time frames for escalating enforcement
actions when appropriate
Identifies priority violations
Includes guidelines for when to seek penalties reflecting
the economic benefit of noncompliance, if feasible
Includes guidelines for seeking and determining higher
penalties for repeat violators
Includes guidelines for inspectors to handle predetermined
citation categories form observation to justice court
Enforcement action options include issuing an Order of Abatement,
filing a Misdemeanor Complaint in Justice court, or asking the County
Attorney to seek a civil penalty in Superior Court.
Inspectors handle certain predetermined citation category
violations and will be responsible for case development from observance
of a violation to filing of the actual citation in the justice court.
Having the inspectors handle routine cases enables the enforcement
officers to work on
[[Page 50273]]
resolving cases involving more serious and complicated violations.
Public Outreach/Education
Public outreach and education consists of staff training, educating
the regulated parties, developing good working relationships with other
involved parties such as the cities, and making the program more
understandable. Increased education of both inspectors and the
regulated industry increases compliance.
Among the public outreach and education efforts will be:
Inspector training on case development.
Inspector training on revised test methods.
City staff training on preparing inspection reports and
notices of violation.
On-going training at the local community college.
Making information available on MCESD website.
Distribution of information through city building
departments and other sources.
In 2000, MCESD revised its dust control guidelines with its
partners ADOT and Arizona State University. This year ADOT secured a
research grant directed towards developing educational tools and
outreach programs. This product will enhance the current guidelines,
add information on the life cycle costs of controls and controls'
impact on the construction process, and develop additional outreach
tools. In addition, MCESD is currently working with two contractors to
develop a model environmental management system for construction. These
two efforts will add to the technical knowledge on dust control and
offer additional tools for companies to increase compliance with
regulations.
Program Evaluation and Tracking
MCESD committed to track the number of inspections, number and type
of enforcement actions, amount of penalties assessed, and amount of
penalties collected. It also committed to conduct mid-year reviews of
the program in September, 2000 and again in March 2001 to evaluate
progress and future needs.
MCESD conducted its reviews and will conduct then again in
September, 2001 and again in March 2002 to evaluate progress and future
needs. In 2000, MCESD conducted 6625 inspections. In the first year of
operation under the new enforcement process, it issued 189 violations,
processed 145 settlement cases and netted $425,000 in fines (May 1,
2000 to April 30, 2001).
G. Attainment Date Extension
Section 188(e) of the Act allows us to extend the attainment date
for a serious area for up to five years beyond 2001 if attainment by
2001 is impracticable. However, before we may grant an extension of the
attainment date, the State must first:
1. apply to us for an extension of the PM-10 attainment date beyond
2001,
2. demonstrate that attainment by 2001 is impracticable,
3. have complied with all requirements and commitments applying to
the area in its implementation plan,
4. demonstrate to our satisfaction that its serious area plan
includes the most stringent measures that are included in the
implementation plan of any state and/or are achieved in practice in any
state and are feasible for the area, and
5. submit SIP revisions containing a demonstration of attainment by
the most expeditious alternative date practicable.
We evaluate the Maricopa County serious area plan's compliance with
each of these requirements below.
1. Apply for an Extension
A state must apply for an extension and concurrently submit a SIP
revision containing a demonstration that the area will attain by the
most expeditious alternative date practicable. The state must provided
the public reasonable notice and a hearing on the application before it
is sent to EPA.
MAG, as the lead air quality planning agency for the Phoenix
metropolitan area, formally requested an extension of the PM-10
nonattainment deadline to December 31, 2006. The documentation
supporting this request is found in Chapter 10 of the MAG plan and
Appendix C, Exhibit 5 of the MAG plan. MAG plan, p. 10-2. This
extension request is an integral part of the MAG plan and was subject
to public hearing along with the rest of the plan, including the
demonstration that the area will attain the 24-hour standard by the
earliest alternative date practicable.
2. Demonstrate the Impracticability of Attainment by December 31, 2001
CAA section 189(b)(1)(a)(ii) and our proposed policy on extension
requests require that the serious area plan must show that the
implementation of BACM (as determined by our guidance) on significant
sources categories will not bring the area into attainment by December
31, 2001 in order to claim that attainment by that date is
impracticable.
To evaluate the impracticability of attainment by 2001, the MAG
plan evaluated the impact of BACM on sources at both the West Chandler
and Gilbert sites in 2001. The evaluation showed these BACM-level
controls left 24-hour PM-10 levels well above the 24-hour standard at
both sites in 2001, thus demonstrating attainment is impracticable by
then. MAG plan, Appendix C, Exhibit 3, pp. 3-10 and 3-11.
In this demonstration, the MAG plan assumes controls only on the
``permitted'' sources, that is, only on those sources that receive
permits from MCESD. The plan assumes that all ``nonpermitted''
sources--unpaved roads, vacant lots, and unpaved parking lots--are
uncontrolled in 2001. MAG plan, Appendix C, Exhibit 3, pp. 3-10 and 3-
11. This latter assumption does not reflect the efforts by MCESD to
assure the implementation of BACM on these sources and is inconsistent
with the assumptions made for these sources in the annual standard
impracticability demonstration.
To check to see if using consistent assumptions between the annual
standard and 24-hour standard demonstrations would show that attainment
of the 24-hour standard is practicable by 2001, we recalculated the
2001 impacts at each monitor using the control assumptions from the
annual standard demonstrations and additional control information from
the BMP TSD. In these recalculations, we assume that the sources at the
microscale site are in full compliance with the applicable rule. See
the ``Extension Request--Demonstrate the Impracticability of Attainment
by December 31, 2001'' in the EPA TSD.
Our recalculations show that attainment of the 24-hour standard at
the West Chandler site remains impracticable by 2001. The principal
sources at this site are an agricultural field, its apron, and a
construction site. The site needs substantial reductions, in excess of
50 percent, in agricultural emissions in addition to controls on the
construction site before the 24-hour standard can be attained. This
level of emission reduction from agricultural sources is not expected
until 2006.
However, our recalculations show that attainment of the 24-hour
standard at the Gilbert site is practicable by 2001. The site's primary
source, an unpaved parking lot, is subject to full control under Rule
310.01 by 2001 and controls on this source together with controls on
the other major source at Gilbert, a vacant lot (also required by Rule
310.01) result in the site showing attainment by 2001.
In order to show attainment, a plan must show attainment at each
location
[[Page 50274]]
within the nonattainment area. Because the West Chandler site is still
unable to show attainment of the 24-hour standard by 2001, the Phoenix
nonattainment area as a whole is unable to show attainment by that
date. Thus the MAG plan's conclusion that attainment of the 24-hour
standard in the Phoenix area is impracticable by December 31, 2001 is
correct. We, therefore, propose to find that attainment of the 24-hour
standard is impracticable by December 31, 2001.
3. Complied With Commitments and Requirements in the SIP
We interpret this criterion to mean that the state has implemented
the emissions reducing measures in the plan revisions it has submitted
to address the CAA requirements in sections 172 and 189 for PM-10
nonattainment areas.
The two SIP revisions that Arizona has submitted to address PM-10
are the 1991 MAG moderate area plan and the 1997 Microscale plan.
The 1991 MAG plan includes a broad range of measures to address PM-
10 including controls for constructions sites, paved road, unpaved
roads, unpaved parking areas, vacant lots, and woodburning. The
principal controls in this plan were Rule 310 and the County
woodburning ordinances. The 1991 plan also included reasonably
available control technology for stationary sources and a wide range of
transportation control measures. The implementation of the measures in
this plan are described in the MAG plan at pp. 10-10 to 10-25. The plan
also contained a large number of commitments from the local
jurisdictions to implement various measures. Most of the measures
represented ``business as usual'' actions by the jurisdictions to do
infrastructure (e.g., road) improvements, to implement existing
building codes or take actions already underway for the carbon monoxide
plan. MAG plan, pp. 10-13 through 10-24.
The 1997 Microscale plan focused on fugitive dust sources such as
construction sites, vacant lots, unpaved roads, unpaved parking lots,
and agriculture. The principal controls in this plan were improvements
to the implementation of Rule 310 and coordination with the cities to
improve fugitive dust control. Implementation of the measures in the
Microscale plan are discussed in Maricopa County commitments, 1998
Revised Measure 6.
From available information in the MAG plan, we believe that the
commitments and requirements in these earlier plans have been met. We,
therefore, propose to find that the State has complied with the
requirements and commitments in its implementation plan.
4. Include the Most Stringent Measures
In our proposed policy for granting extension requests under CAA
section 188(e), we suggest a 5-step process for identifying and
adopting MSM. See section V.B.4. of this preamble. This process is
similar to the one we have established for determining BACM, but with
one additional step, to compare the potential MSM against measures
already adopted in the area to determine if the existing measures are
most stringent.
The first two steps in our proposed MSM policy are to develop a
detailed emissions inventory of PM-10 sources and source categories and
to model to evaluate the impact on PM-10 concentrations over the
standards of the various source categories to determine which are
significant for the purposes of adopting MSM. The MAG plan, however,
excludes no source categories of directly-emitted PM-10 from its MSM
analysis and moves directly to the third step in the MSM determination,
identifying potential MSM in other implementation plans or used in
practice in other states for each source categories present in the
Phoenix area. MAG plan, p 10-25.
To identify candidate MSM, MAG's contractor Sierra Research
interviewed people knowledgeable about PM-10 controls, reviewed the
documents used to develop the candidate list of BACM and obtained
copies of current air quality control measures from most other States
including both SIP and non-SIP measures. MSM Study, p. 1-2.
The fourth step in our proposed policy for MSM is to compare the
potential MSM for each significant source category against the
measures, if any, already adopted for that source category in the local
area. In the MAG plan, after a comprehensive list of candidate MSM was
developed, each measure was screened against the corresponding Maricopa
measure to identify those with more restrictive emission limitations,
more extensive lists of affected sources, fewer exemptions, and/or one
or more substantive regulatory provisions not found in the Maricopa
measure.
The final step in our proposed policy for MSM is to provide for the
adoption of any MSM that is more stringent than existing similar local
measures and provide for implementation as expeditiously as practicable
or, in lieu of providing for adoption, provide a reasoned justification
for rejecting the potential MSM, i.e., why such measures cannot be
feasibly implemented in the area. In the MAG plan, MSM that remained
after the screening in step 4 were grouped by source category and were
either included in the plan or a reasoned justification for rejecting
the measure was provided. MSM study, Table 3-1, MAG plan, p. 10-46, and
BMP TSD, pp. 19 to 27.
Based on our analysis of the MAG plan's provisions for identifying
and adopting MSM, we propose to find that the MAG plan demonstrates to
our satisfaction that it includes the most stringent measures that are
included in the implementation plan of any State, or are achieved in
practice in any State, and can be feasibly be implemented in the
Phoenix area.
We have discussed identification and adoption of MSM and the
rejection of any MSM for each category deemed significant for BACM
earlier in this preamble. The MAG plan identifies three MSMs for
categories considered de minimis in the BACM analysis. These categories
are cattle feed lots, incinerators, and charbroilers.
Cattle feed lots: MCESD Rule 310.01 requires that owners/operators
of commercial feedlots and/or livestock areas apply dust suppressants,
apply gravel, or install shrubs and/or trees within 50 to 100 feet of
animal pens. The MAG plan identifies South Coast Rule 1186 requirements
for livestock operations as a potential MSM for commercial feedlots/
livestock areas. However, the two rules control different emission
activities at commercial feedlots/livestock areas. South Coast Rule
1186 requires controlling unpaved roads and hay grinding at dairy and
horse farms but does not address fugitive dust emissions from disturbed
open areas. MCESD Rule 310.01 controls fugitive dust emissions from
disturbed open areas at dairies and cattle lots but not unpaved roads
and hay grinding.
In the Maricopa County PM-10 nonattainment area, there is only one
cattle feedlot and fewer than 80 dairies (most of which are actually
outside the nonattainment area). Unpaved roads at dairies are low
travel (10 to 20 ADT) and represent a very small source of emissions in
the Phoenix area and controls on them would not advance the attainment
date and are not necessary for expeditious attainment. We, therefore,
propose to find that the MAG plan provides for the implementation of
MSM to our satisfaction without Rule 1186 provisions for unpaved roads
at cattle feed lots.
In Maricopa County, hay grinding activities occur primarily at feed
mills (as opposed to dairies) which are
[[Page 50275]]
permitted sources and thus already subject to control requirements.
Incinerators: The MAG plan identifies Clark County's Rule 26 as
having a more stringent opacity limit than MCESD's Rule 313. Clark
County limits opacity from existing incinerators to 5 percent while
Maricopa's limit is 20 percent. MAG plan, Table 10-7. Incinerators are
a very small source in the Phoenix nonattainment area. In 1994 there
were 32 incinerators that together emitted 2.56 metric tons per year
(7.1 kg per day). 1994 Regional PM-10 Inventory, p. 4-17. Since then,
the medical waste incinerators in this category have shut down and
today there are even fewer emissions. Because incinerators are a
trivial source and controls on them would not advance the attainment
date and are not necessary for expeditious attainment, we propose to
find that the MAG plan provides for the inclusion of MSM to our
satisfaction without including Clark County's opacity limit for
incinerators.
Charbroiling: Emissions from charbroiling and frying meat are
estimated to be 0.6 mtpd or 227 mtpy. 1994 Regional PM-10 Inventory, p.
4-25. This is 0.4 percent of the daily directly-emitted PM-10 inventory
in 1994 and 0.4 percent of the annual inventory in 1994. MCESD has
committed to develop a new rule to require existing and new chain-
driven and underfired charbroilers, typically found in restaurants
specializing in grilled meat products, to be equipped with emission
control equipment. South Coast AQMD is developing a new rule to deal
with underfired charbroilers and MCESD will wait until South Coast
completes its rulemaking, now scheduled for late 2001, to adopt this
measure. Maricopa County commitments, Revised Measure 23. We propose to
find that implementation of this rule is expeditious. Waiting on South
Coast to complete its rulemaking, which will establish control
requirements for underfired charbroilers, is appropriate given that the
South Coast rule when adopted will establish MSM for controls on these
types of charbroilers.
5. Demonstrate Expeditious Attainment
For the reasons discussed below, we propose to find that the MAG
plan demonstrates attainment by the earliest date practicable after
December 31, 2001 as required by CAA section 189(b)(1)(A)(ii). We also
propose to find that the attainment demonstration relies on control
measures that either are approved or have been proposed for approval
and meet our SIP enforceability criteria; that the emissions estimates
credited to these measures in the attainment demonstration are
reasonable; and the measures are being implemented on a schedule that
is as expeditious as practicable and will result in attainment by the
earliest practicable date.
The following is a brief summary of our evaluation of the modeling
in the MAG plan. Our full evaluation is in the EPA TSD section
``Extension Request-Demonstrate Attainment by the Most Expeditious
Alternative Date Practicable after December 31, 2001.''
a. Air Quality Modeling
The attainment demonstration for the 24-hour standard is divided
into two parts, a microscale analysis and a regional analysis. The
microscale part evaluates 24-hour exceedances at four monitoring sites
in the Phoenix area using a version of the industrial source complex
(ISC) model. The regional part evaluates 24-hour levels throughout the
rest of the Maricopa County nonattainment area using the Urban Airshed
Model-Linear Chemistry version (UAM-LC).
As discussed previously, Arizona has made three submittals that
contain elements of the attainment demonstration for the 24-hour PM-10
standard: the 1997 Microscale plan, the 2000 revised MAG plan, and the
2001 BMP TSD. A more complete description of these submittals can be
found in section 2 of this preamble and in section 1 of the EPA TSD. We
briefly describe here how these submittals fit together to create the
overall attainment demonstration for the 24-hour standard.
The first of the three submittals, the 1997 Microscale plan,
contains a microscale, or localized, inventory and modeling analysis
using the ISCST model of 24-hour standard exceedances at four
monitoring sites in the Phoenix area: Maryvale, Salt River, West
Chandler and Gilbert. It shows attainment of the standard at the
Maryvale and Salt River sites but does not demonstrate attainment for
the Gilbert and West Chandler sites, both of which were substantially
affected by agricultural sources.\40\
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\40\ Because we have already approved the attainment
demonstrations at the Maryvale and Salt River sites, we do not
further discuss these sites in this proposal. See 62 FR 41856,
41863.
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The second submittal, the 2000 revised MAG plan contains a regional
modeling analysis of 24-hour standard exceedances using UAM-LC. It also
uses the ISCST model to determine that a 58 percent reduction in
agricultural emissions is needed to attain the 24-hour standard at the
West Chandler site and 20 percent at the Gilbert site.\41\ However, at
the time of its submittal, Arizona had not yet completed adoption of
its BMP general permit rule and also had not yet quantified the
expected reductions from rule and thus was unable to model the impact
of the rule at these two sites.
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\41\ See p. 3-9 in ADEQ, ``Evaluation for Compliance with the
24-hour PM-10 Standard for the West Chandler and Gilbert Microscale
Sites,'' June 1999 (ADEQ TSD), found in Appendix C, Exhibit 3 of the
MAG plan.
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The third submittal, the 2001 BMP TSD, documents the expected
emission reductions from the BMP general permit rule. This submittal
does not contain new modeling but rather shows that the rule's emission
reductions, together with a reasonable estimate of land use change,
provide greater reductions than needed for attainment at the Gilbert
and West Chandler sites.
1. Modeling Approach to the 24-Hour PM-10 Standard Attainment
Demonstration
Our guidance on attainment demonstrations generally assumes that
the entire nonattainment area will be modeled using a dispersion
model.\42\ However, emissions inventory development and modeling for
areas with substantial fugitive dust problems, such as the Phoenix
area, have proved difficult, because of fugitive dust emissions' marked
uncertainty and their temporal and spatial variability. Accurately
estimating emissions for input to dispersion modeling of fugitive dust
over a large area is much more difficult than for point sources of
gaseous pollutants, which were the archetypes for development of much
of our modeling guidance.
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\42\ A dispersion model models how emissions from sources are
dispersed into the atmosphere based on local wind patterns and
speeds and other meteorological parameters. The two principal inputs
into a dispersion model are temporally- and spatially-distributed
emissions and meteorological information.
---------------------------------------------------------------------------
Thus, in areas dominated by fugitive dust sources, the approach of
intensively inventorying and modeling a small area is a reasonable one.
This approach is also more reflective of the nature of fugitive dust.
Fugitive dust PM-10 is emitted near ground level and has relatively
sharp spatial gradients as dust settles out with distance from the
source, and hence has more localized effects than the other criteria
pollutants, which are typically buoyant and gaseous.
Under the microscale approach used in the MAG plan, the areas
around the exceeding monitors are deemed to be representative of
locations throughout the nonattainment area. Attainment is
[[Page 50276]]
demonstrated at locations representing the various mixes of emission
sources that occur in the area. Although a specific emitting activity,
such as new housing construction, will eventually decline in a given
location, it will reappear elsewhere as the metropolitan area grows. A
location that is currently experiencing a lot of construction can thus
be used to represent locations where construction will occur in the
future. Moreover, in the MAG plan all locations exceeding the 24-hour
PM-10 standard in 1995 were subjected to analysis. A demonstration of
attainment at these locations will show that the mixes of sources that
caused exceedances in the Phoenix area will be controlled sufficiently
to meet the standard.
Although there is solid reasoning underpinning the microscale
approach in a fugitive dust-dominated area such as Phoenix, there is
concern that for a large urban area the sheer number of sources,
especially fugitive dust area sources, could make for a pervasive
regional component of PM-10 in addition to the more localized or
microscale component. Additionally, a portion of PM-10 is fine
particles, which can stay suspended longer and so can be transported
greater distances than coarse particulate.
Fine particulate includes secondary particulate, which forms
chemically in the air from precursors like ammonia and oxides of sulfur
and nitrogen. Secondary particulate is formed by chemical reactions in
a mixture of emissions from various sources, spread over hours and a
spatial scale of 10's of kilometers. Like ozone, it is a regional
pollutant, and so needs to be modeled on a larger scale. Although only
a small fraction (4 percent) of the total PM in the Maricopa area,
secondary particulate is present. While this regional component could
partly be addressed by adding a background concentration to microscale
modeling, the determination of a background is ambiguous since it
includes the effect of sources similar to those in the microscale
domain. For these reasons, the MAG plan include regional modeling in
addition to the microscale analysis.
2. EPA's Review of the Air Quality Modeling in the MAG Plan
In today's proposal, we focus our discussion on the supplemental
microscale modeling for the Gilbert and West Chandler sites in the ADEQ
TSD and the evaluation of the agricultural general permit rule in the
BMP TSD. We have already extensively reviewed both the microscale
modeling and the regional modeling in previous proposals and found them
acceptable. See our proposal on the Microscale plan at 62 FR 31025,
31029 and the proposal on the annual standard at 65 FR 19964,
19985.\43\ See also the EPA TSD section on ``Extension Request-
Demonstrate Attainment by the Most Expeditious Alternative Date
Practicable after December 31, 2001.''
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\43\ For the regional model, 65 individual days were analyzed in
the base year and attainment year, that is, MAG ran the UAM-LC model
for each of these 65 24-day days. To evalute the 24-hour standard,
the individual results from each one of these modeling runs are
used. To evaluate the annual standard, the results from all the
modeling runs for each year are averaged together. Thus, in
reviewing the modeling for the annual standard demonstrations, we
necessarily also reviewed the modeling for the regional 24-hour
standard demonstrations.
---------------------------------------------------------------------------
The approach used for the supplemental modeling in the ADEQ TSD is
essentially the same approach used in the Microscale plan. They differ
in just three ways. First, the ADEQ TSD uses a new calculation of
background concentrations (that is, the impact on ambient PM-10 levels
in the microscale area of sources outside the microscale area). Second,
it evaluates PM-10 concentrations at multiple locations within the
microscale domain. Finally, it evaluated various levels of reductions
from agricultural controls, in order to determine the emission
reductions needed for attainment.
New background values were calculated in order to reflect the
regional implementation of controls. These controls reduce the
contribution to ambient PM-10 levels in the microscale area of sources
outside the microscale area. To recalculate the background values, ADEQ
split the background between windblown and non-windblown contributions,
applying controls only to the windblown contribution. See ADEQ TSD, p.
3-7.
The evaluation of PM-10 concentrations at multiple locations within
the microscale area is an improvement to the previous microscale
modeling. In the Microscale plan, the evaluation was limited to the
actual location of the ambient air quality monitor within the
microscale domain.
The evaluation of the emissions reductions needed for attainment in
2006 at the West Chandler site (assuming a 90 percent level of control
on the construction site) showed that a 58 percent reduction in
emissions from agricultural aprons and fields was needed. For the
Gilbert site, a 20 percent emission reduction is shown to be needed
from the agricultural apron. ADEQ TSD, pp. 3-9.
The BMP TSD shows that BMP general permit rule, together with a
reasonable estimate of land use changes, provide a 60.3 percent
reduction by 2006. This reduction is sufficient to demonstrate
attainment by 2006 at West Chandler. For the Gilbert site, the rule
provides more than the 20 percent needed for attainment by 2006. BMP
TSD, p. 9.
This 60.3 percent reduction at the West Chandler site is a
combination of a 36.6 percent emissions reduction from the BMP general
permit and a 37 percent emissions from the conversion of agricultural
land to residential and commercial use.\44\ This land use conversion
rate is derived from a land use model for the overall nonattainment
area and represents the reduction regionally in agricultural lands
between 1995 and 2006. BMP TSD p. 28.
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\44\ The reductions are not additive because the BMP general
permit rule reduces emissions only from the land left in
agricultural production. The overall control effectiveness is
calculated as the percent lost agricultural lands + BMP rule
effectiveness * percent remaining agricultural lands or 37% +
0.366*63%.
---------------------------------------------------------------------------
Under the microscale approach, the areas around the exceeding
monitors are deemed to be representative of locations throughout the
nonattainment area. Thus, applying regionally the controls needed for
attainment at these representative sites is assumed to assure
attainment at similar sites throughout the nonattainment area. One
aspect of this approach, which was not adequately explored in earlier
submittals, is to how to treat the inevitable changes in land uses and
activities within the microscale domains. For example, construction
activity, like that at the West Chandler site, will eventually be
completed and no longer contribute to emissions in the area.\45\
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\45\ In fact, at the West Chandler site, the construction is
complete and agricultural land has been converted to residential and
commercial uses.
---------------------------------------------------------------------------
A land use and socioeconomic model, in conjunction with a
dispersion model, could legitimately show that exceedances no longer
occur in the area simply based on this change in land use. However,
just waiting for land use changes alone to reduce emissions is not an
acceptable method of demonstrating attainment at the individual
microscale sites because once again, the premise underlying the
microscale approach is that each site is representative of other
similar areas in the nonattainment area. In a growing metropolitan area
like that of Phoenix, there will always be areas with on-going
construction.
On the other hand, the opposite extreme of assuming no conversion
of agricultural lands at all does not seem reasonable either. The
reality is that the
[[Page 50277]]
metropolitan area is growing and agricultural land is rapidly being
converted. Such changes have been observed over the past decades and
are projected to continue.
In this situation, using an estimate from the area's land use model
of the conversion of agricultural lands to occur by 2006 is a
reasonable approach to use. This approach is a compromise between the
extremes of the no-conversion and the total-conversion assumptions. It
is driven by the area's socioeconomic projections that are used for
many purposes and represent the best available information about the
land use changes the overall area will experience.
Also, using an area average figure is consistent with the area wide
application of control measures required under the submittal's
approach. Reliably predicting the conversion for a particular small
area (several square miles in the microscale approach) would be
problematic in any case, since it would depend on knowing individuals'
purchase decisions and development plans. Aggregate conversion figures,
driven by larger economic forces and representing the average of many
actions, should be more reliable.
Assuming some land use change is more in line with the traditional
use of microinventories in EPA's PM-10 attainment demonstration
guidance, and also is in line with how attainment demonstrations are
performed in general. Typically the projections for land use,
employment, industrial production, population, vehicle traffic, etc.
are part of the baseline conditions assumed in projecting future air
quality; in an attainment demonstration they are independent of, but
used in conjunction with, estimates of control measure effectiveness.
In other words, reductions that occur naturally because of
socioeconomic changes are implicitly counted in attainment
demonstrations. Conversely, growth in emission sources, e.g., vehicle
traffic, are also implicitly counted and must be compensated for by
additional emission reductions.
In summary, we believe that the approach used in 2001 BMP TSD,
while not completely consistent with how the microscale approach was
implemented in the 1997 Microscale plan, nevertheless, is a reasonable
balance between different possible implementations of a microscale
approach. Overall, we propose to find that technical evaluation in the
MAG plan is adequate to support the attainment demonstration for the
24-hour standard at the West Chandler and Gilbert sites.
b. Control Measures Relied on for Attainment
For demonstrating attainment of the 24-hour PM-10 standard, the MAG
plan relies on reductions in directly-emitted PM-10 from 3 measures:
MCESD's Rules 310 and 310.01 and the agricultural BMP general permit
rule. ADEQ TSD, pp. 3-3 to 3-6 and BMP TSD, p. 8. We have proposed to
approve all of these measures. See 65 FR 19992, 19989 and 66 FR 34598.
As part of these proposed approvals, we have evaluated each of
these measure to ensure that it meets our SIP enforceability criteria.
These criteria ensure that the measure's compliance requirements-
applicability, performance standards, compliance schedule, and
monitoring methods--are clear. For MCESD's rules, see sections on
proposed approval of Rule 310 and 310.01 in the TSD supporting the
annual standard proposal. For the agricultural general permit rule, see
66 FR 34598.
We have also evaluated the emissions reductions credited to each
measure in the attainment demonstrations to ensure they are reasonable.
In performing the microscale analysis, ADEQ first determined that each
significant, non-agricultural source at the microscale sites (e.g., the
unpaved parking lot at the Gilbert site) was large enough to be subject
to Rules 310 or 310.01.\46\ For each of these sources, ADEQ then
applied the control factor used in the Microscale plan for that source.
Except for the agricultural sources, it did not use rule effectiveness
factors for either the sources in the microscale component or the
sources in the windblown background component in the attainment
demonstrations.
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\46\ Rule 310 and Rule 310.01 do not apply to sources under a
certain size. For example, Rule 310.01 does not apply to vacant lots
under 0.1 acres. Rule 310.01, section 301.
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Rule effectiveness (RE) accounts for emission reductions lost
because of noncompliance, control equipment downtime, failure to apply
adequate controls, or failure to use control equipment properly. One
hundred percent rule effectiveness is the ability of a regulatory
program to achieve all the emission reductions that could be achieved
by full compliance with the applicable regulations at all sources at
all times. Because RE factors are intended to reflect the variations in
compliance among large numbers of sources, they are applied to source
categories rather than to individual sources.
We agree that it is appropriate not to apply an RE factor to the
individual sources at each microscale site; \47\ however, we believe
that an RE factor should be applied to the windblown background source
categories because each category represents multiple sources. To
determine the effect of applying the RE factor to sources in the
windblown background, we re-evaluated the attainment demonstrations at
both Gilbert and West Chandler. We found that the plan still
demonstrates attainment of the 24-hour standard as expeditiously as
practicable. See EPA TSD section ``Extension Request-Demonstrate
Attainment by the Most Expeditious Alternative Date Practicable after
December 31, 2001,''
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\47\ At each microscale site, there is only a single source in
each category, that is there is a single vacant lot, a single
construction site, a single agricultural field with its apron, a
single unpaved parking lot.
---------------------------------------------------------------------------
We find that the emission reduction estimates for each source
category are consistent with research on the applicable control methods
and are appropriately applied in the attainment demonstrations. For
more information on the quantification of emission reductions from
Rules 310 and 310.01 see the section ``Extension Request-Demonstrate
Attainment by the Most Expeditious Alternative Date Practicable after
December 31, 2001'' in the EPA TSD for the annual standard proposal.
For more information on the quantification of emission reductions from
the agricultural general permit rule, see the section ``Implementation
of BACM and Inclusion of MSM for Agricultural Sources'' in the EPA TSD
for this proposal.
We have also determined that the measures relied on for attainment
are being expeditiously implemented. Rule 310 and 310.01 are effective
now. Implementation of the agricultural general permit rule began in
July 2000 and will be completed by December 31, 2001.
6. Other Factors That EPA May Consider
CAA section 188(e) list five additional factors that we may
consider in deciding whether to grant an extension and the length of
that extension.
The MAG plan provides information addressing each of the factors in
Chapter 10 of the plan. Nothing in this additional information
presented on the five factors suggests that granting an extension of
the attainment date for the Phoenix area to 2006 is inappropriate.
a. Nature and Extent of Nonattainment
In the Phoenix area, elevated 24-hour levels of PM-10 occur mainly
in areas with large fugitive dust sources or with a concentration of
fugitive dust sources.
[[Page 50278]]
Areas such as this can be found throughout the Phoenix
nonattainment area, so we would expect that there are elevated 24-hour
PM-10 levels throughout the Phoenix area. In order to attain the 24-
hour standard in this situation, controls need to be uniformly
implemented throughout the area, a task that generally requires longer
to achieve than implementing controls in a few localized areas.
b. Types and Numbers of Sources or Other Emitting Activities
Primary contributors to elevated PM-10 levels are fugitive dust
sources including paved road dust, unpaved roads, construction
activities, disturbed vacant lands, unpaved parking lots, and
agricultural sources. MAG plan, p. 10-51. These sources are ubiquitous
in the nonattainment area and collectively number in the thousands. For
example, MCESD issued 2500 construction permits in 1999; we mailed
50,000 letters to owners of vacant lots in the nonattainment area to
inform them of our FIP fugitive dust rule; there are 12,000 miles of
roadway in the nonattainment area.
c. Population Exposure to Concentrations Above the Standard
The MAG plan estimates population exposure to elevated levels of
PM-10 (both annual and 24-hr) to be from 78,000 to 163,000 (1995
figure), p. 10-13. This population exposure is calculated using
estimates of disturbed land versus population in subareas of the
nonattainment area. According to this calculation, 84 percent of
Maricopa's population lives in areas where 10 percent or less of the
land is open. MAG plan, Table 10-13. However, the plan does provide for
implementation of RACM, BACM, and MSM on disturbed land (including
construction) and paved and unpaved roads with much of the emission
reductions being achieved in the first few years. All these factors
will reduce population exposure as quickly as practicable.
d. Presence and Concentration of Potentially Toxic Substances in
the Particulate
The primary source of airborne cancer risk in the Maricopa area is
internal combustion engine exhaust from both on and nonroad engines.
This risk is from all pollutants emitted from these sources (gaseous
and particulate). MAG plan, p. 10-61. The MAG plan concludes that the
cancer risk in the Phoenix area is comparable to that in California
cities, p. 10-61. The MAG plan and other Arizona programs (e.g.,
cleaner burning gasoline, national emission standards for nonroad
engines) target emissions from on and nonroad engines.
Almost all of the PM-10 emission reductions in the out years of the
MAG plan (2003 and later) are and need to be from fugitive dust sources
in order to show attainment of the 24-hour PM-10 standard and not from
on- and nonroad engines; therefore, extending the attainment date does
not affect the degree of public exposure to the major source of toxic
risk because shortening the extension would not accelerate controls on
the major source of toxic risk, on- and nonroad engines.
e. Technological and Economic Feasibility of Controls
Fugitive dust sources dominate the emissions inventory in the
Maricopa nonattainment area and are the most significant contributors
to 24-hour PM-10 exceedances. Controls for these sources are well known
(paving, wetting surfaces, etc.) and have been adopted; however, the
number of sources and nature of sources make education and outreach
necessary to assure full compliance with those controls. In addition,
costs for paving roads and other capital improvements needed to reduce
PM-10 emissions are high and necessary funds are only available over a
number of years. These factors generally support a longer time frame
for attainment.
7. Conclusion on Extension Request
Based on our review of the MAG plan and our proposed determination
that it meets the requirements necessary for granting an extension of
the attainment date under CAA section 188(e), we are proposing to grant
a five-year extension of the attainment date for the 24-hour PM-10
standard in the Phoenix PM-10 serious nonattainment area from December
31, 2001 to December 31, 2006.
H. Reasonable Further Progress and Quantitative Milestones
CAA section 172(c)(2) requires nonattainment plans to provide for
reasonable further progress (RFP). Section 171(1) of the Act defines
RFP as ``such annual incremental reductions in emissions of the
relevant air pollutant as are required by this part [part D of title I]
or may reasonably be required by the Administrator for the purpose of
ensuring attainment of the applicable national ambient air quality
standard by the applicable date.''
CAA section 189(c) also requires PM-10 plans demonstrating
attainment to contain quantitative milestones which are to be achieved
every 3 years until the area is redesignated attainment and which
demonstrate RFP. These quantitative milestones should consist of
elements that allow progress to be quantified or measured. Addendum at
42016.
1. Reasonable Further Progress
The MAG plan provides for annual progress toward attaining the 24-
hour standard. This demonstration shows that most of the projected
reductions occur after 2001; however, this is an artifact of the
assumption that there are no controls on agricultural sources, vacant
lots and unpaved parking prior to December 31, 2001. This assumption
does not reflect the efforts by MCESD to assure the implementation of
BACM on these sources and the requirement for BMPs to be implemented by
then. If the RFP demonstration is revised to include emission
reductions from BACM on these sources, then the majority of the
emission reductions occur before 2001. See the ``Reasonable Further
Progress and Quantitative Milestones'' section in the EPA TSD.
In order to demonstrate RFP, the plan first regionalizes the
inventories at the two microscale sites by multiplying emissions from
each source by a factor of 360, which is the ratio of the size of the
nonattainment area (2,880 square miles) to the size of the microscale
sites (8 square miles). It then calculates the emission reductions from
the application of the adopted measures to these sources. Next, it
annualizes these emission reductions by multiplying the sources--which
are all windblown sources--by 11, the number of windy days in 1995.
Finally, the annualized figure is divided by 365 days to get an average
annual day emission reductions. See BMP TSD, pp. 29--31.\48\
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\48\ There was an error in the original RFP calculation on pages
29 to 31 in the BMP TSD. ADEQ corrected this error and provided us a
revised RFP and contingency measure demonstrations and quantitative
milestones in a letter. See letter, Jacqueline E. Schafer, ADEQ, to
Laura Yoshii, EPA, ``Addendum to June 13, 2001, Submittal of State
Implementation Plan revision for the Agricultural Best Management
Practices program in the Maricopa County PM-10 Nonattainment Area,''
September 7, 2001 (``ADEQ RFP Addendum Letter'')
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Regionalizing and annualizing the microscale inventories is a good
approach to demonstrating RFP and establishing milestones for the 24-
hour standard in the Phoenix area. Just a few source categories are
explicitly identified contributors to exceedances of this standard, and
it is effective controls on these categories that are necessary for
progress and attainment. Therefore, closely tracking the effect of
[[Page 50279]]
those controls on these source categories is essential. Regionalizing
and annualizing the microscale inventories allows this to be done.
The plan does not provide emission reduction information for each
year between the base modeling year of 1995 and the attainment year of
2006. We do not believe that this level of detail is necessary or
meaningful given the evidence that progress is being made over time and
the implementation of controls are not being delayed. Therefore, we
propose to find that the MAG plan provides for ``such annual
incremental reductions in emissions of the relevant air pollutant as
are required by this part [part D of title I]
or may reasonably be
required by the Administrator for the purpose of ensuring attainment of
the [24-hour PM-10]
national ambient air quality standard by the
applicable date'' as required by section 172(c)(2) of the Act.
2. Quantitative Milestones
Quantitative milestones based on regionalized and annualized
microscale inventories are provided for 2001, 2003, and 2006. See RFP
Addendum Letter, Enclosure 2. These are the same milestone years used
for the annual standard. See 65 FR 19964, 19988. The assumptions
regarding control measures' implementation and effectiveness that
underlie the quantitative milestones are reasonable and consistent with
the RFP demonstration.
The plan does not provide milestones for each of the two microscale
sites. Milestones are intended as checks along the way, a means of
judging actual emission reductions and control measure implementation
against those projected in the plan. Arguably, given the microscale
analysis that is the basis for the Phoenix area's 24-hour standard
plan, quantitative milestones should be established for both the West
Chandler and Gilbert sites. However, this approach would actually
defeat the purpose of the quantitative milestones rather than fulfill
it.
In order to report on a quantitative milestone at the microscale
sites, Arizona would need to evaluate the implementation of controls at
each site. However, land uses and activities around each of these
microscale sites have changed significantly since 1995. For example, at
the West Chandler site, the road construction has been completed and
the agricultural field and its apron have been converted into stores.
Thus, reporting on each site's quantitative milestones would tell us
more about the land use changes around each site than about the
implementation of controls. Because of this, the quantitative
milestones for the 24-hour plan need to reflect regional implementation
of controls. The MAG plan's approach of regionalizing and annualizing
the emissions inventories from the microscale sites and then basing its
RFP demonstration and milestones on the resulting inventory is an
appropriate way to deal with these requirements for the 24-hour
standard.
For these reasons, we propose to find that the MAG plan meets the
quantitative milestone requirement in CAA section 189(c)(1) for the 24-
hour standard.
I. Contingency Measures
Section 172(c)(9) of the Clean Air Act requires that implementation
plans provide for the implementation of specific measures to be
undertaken if the area fails to make RFP or attain by its attainment
deadline. These contingency measures are to take effect without further
action by the State or the Administrator. The Act does not specify how
many contingency measures are necessary nor does it specify the level
of emission reductions they must produce.
We interpret the ``take effect without further action by the State
or the Administrator'' to mean that no further rulemaking actions by
the State or EPA would be needed to implement the contingency measures.
Addendum at 42015.
The purpose of contingency measures is to ensure that additional
emission reductions beyond those relied on in the attainment and RFP
demonstrations are available if there is a failure to make RFP or
attain by the applicable attainment date. These additional emission
reductions will assure continued progress towards attainment while the
SIP is being revised to fully correct the failure. To ensure this
continued progress, we recommend that contingency measures provide
emission reductions equivalent of one year's average increment of RFP.
Addendum at 42016.
Certain core control measure requirements such as RACM, BACM, and
MSM may result in a state adopting and expeditiously implementing more
measures than are strictly necessary for expeditious attainment and/or
RFP. Because of this and because these core requirements effectively
require the implementation of all non-trivial measures that are
technologically and economically feasible for the area, states are left
with few, if any, substantive unimplemented control measures. In fact,
under the Act's PM-10 planning provisions, if there were a measure or
set of measures that were technologically and economically feasible and
could collectively generate substantial emission reductions, e.g., one
year's worth of RFP, then a state would be hard pressed to justify
withholding their implementation.\49\
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\49\ We do not believe that States are obligated by section
172(c)(9) to adopt infeasible or unreasonable measures or measures
that individual or collectively have trivial benefit.
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If we read the CAA to demand that the only acceptable contingency
measure are those that are adopted but not implemented, then states
face a difficult choice: adopt the controls for immediate
implementation and clearly meet the core control measure requirements
but fail the contingency measure requirement or adopt the control
measures but hold implementation in reserve to meet the contingency
measure requirement but potentially fail the core control measure
requirements.
However, states do not need to face this difficult choice if we
read the CAA to allow adopted and implemented measures to serve as
contingency measures, provided that those measures' emission reductions
are not needed to demonstrate expeditious attainment and/or RFP. There
is nothing in the language of section 172(c)(9) that prohibits this
interpretation. This approach to the contingency measure requirement
also has the benefit of allowing states to build uncredited cushions
into their attainment and RFP demonstrations, which makes actual
failures to make progress or attain less likely, while still obtaining
the air quality and public health benefits from the implemented
measures.
We have allowed this approach, which is effectively the early
implementation of contingency measures, in ozone and carbon monoxide
plans. See memorandum, G. T. Helms, Chief, Ozone/Carbon Monoxide
Programs Brand, OAQPS to Air Branch Chiefs, Regions I-X, ``Early
Implementation of Contingency Measures for Ozone and Carbon Monoxide
(CO) Nonattainment Areas,'' August 13, 1993. In this memorandum, we
note that several states wished to implement their contingency measures
early even though they were not needed for their attainment or RFP
demonstrations and that ``[i]t seems illogical to penalize
nonattainment areas that are taking extra steps to ensure attainment of
the NAAQS by having them adopt additional [replacement]
contingency
measures now.'' This rationale applies with equal force to PM-10 plans.
[[Page 50280]]
Annual Standard
The revised MAG plan as submitted in February 2000 identifies 5
measures as contingency measures with a collective emission reduction
of 5.5 mtpd: the agricultural BMP general permit rule, off-road engine
standards, the clean burning fireplace ordinance, and additional dust
controls from the cities of Tempe and Phoenix. MAG plan, p. 8-19.
Since the MAG plan was submitted, Arizona has made changes to its
contingency measure package for the annual standard. First, Arizona has
withdrawn its commitment to adopt California's off road vehicle
standards because the federal nonroad program produces essentially the
same emission reductions. ADEQ Off-Road Letter. Second, the emission
reductions from the agriculture contingency measure have been
recalculated based on the BMP general permit rule as adopted. The
emission reductions from the revised contingency measures package are
now 6.9 mtpd. See EPA TSD ``Contingency Measures'' for more details on
the emission calculations.
All the measures that have been identified in the MAG plan as
contingency measures have been adopted and are being implemented but
are not credited in the attainment, RFP or milestone demonstrations for
the annual standard and are not necessary to demonstrate expeditious
attainment of that standard. Under our applicable policies, states are
allowed to use implemented but uncredited measures as contingency
measures.
Under our contingency measure policy, we recommend contingency
measures have total emission reductions equal to or more than the
annual RFP increment. For the Phoenix area, the average annual
increment in RFP for the annual standard is 5.5 mtpd/year for the full
11-year period, 1995 to 2006. See EPA TSD, ``Reasonable Further
Progress and Quantitative Milestones.'' Collectively, the specified
contingency measures generate 6.9 mtpd.
Based on this analysis, we propose to find that the MAG plan
provides for the implementation of contingency measures for the annual
standard as required by CAA section 172(c)(9).
24-Hour Standard
The identified contingency measure for the 24-hour standard is
controls for unpaved roads and alleys. BMP TSD, p. 30. This measure
comprises not only the unpaved road provisions in MCESD Rule 310.01 but
also the commitments by local jurisdictions to control unpaved roads.
See MAG plan, pp. 7-75 to 7-94. This measure is estimated to reduce
emissions by 12.19 mtpd in 2006. MAG plan, p. 8-9. The average annual
increment in RFP for the 24-hour standard is 10.9 mtpd/year. See ADEQ
RFP Addendum Letter, Enclosure 1.
The unpaved road measure that is identified in the MAG plan as
contingency measure for the 24-hour standard has been adopted and is
being implemented but is not credited in the attainment, RFP or
milestone demonstrations for the 24-hour standard and is not necessary
to demonstrate expeditious attainment of that standard. Under our
applicable policies, states are allowed to use implemented but
uncredited measures as contingency measures.
Based on this analysis, we propose to find that the MAG plan
provides for the implementation of contingency measures for the 24-hour
standard as required by CAA section 172(c)(9).
J. General SIP Requirements
Section 110(a)(2)(E)(i) of the Clean Air Act requires that
implementation plan provide necessary assurances that the State (or the
general purpose local government) will have adequate personnel, funding
and authority under State law. Requirements for legal authority are
further defined in 40 CFR part 51, subpart L (51.230-51.232) and for
resources in 40 CFR 51.280.
States and responsible local agencies must demonstrate that they
have the legal authority to adopt and enforce provisions of the SIP and
to obtain information necessary to determine compliance. SIPs must also
describe the resources that are available or will be available to the
State and local agencies to carry out the plan, both at the time of
submittal and during the 5-year period following submittal of the MAG
plan.
Other than revisions to Maricopa County's revised commitments to
improve Rule 310, we are not proposing to approve any control measures
in this proposal. All commitments and rules relied on in the MAG plan
to meet the CAA requirements for the 24-hour PM-10 standard are already
approved, were proposed for approval in the annual standard proposal,
or proposed for approval in a subsequent notice. In these notices, we
have already proposed to find that the implementing agencies for the
MAG plan have adequate resources for implementing their respective
commitments and provided an opportunity for comment. We are not
reproposing these findings.
Finally, we initially proposed to find in the annual standard
proposal that all agencies and jurisdictions have adequate authority
under Arizona state law to implement their respective commitments and,
where applicable, to obtain information necessary to determine
compliance. 65 FR 19964, 19989. While minor changes have been made to
several control measures (e.g., the remote sensing program), the State
continues to have adequate authority to implement the measures. No
other changes have been made to any agencies and/or jurisdictions
authority since we proposed the annual standard.
Section 110(a)(2)(C) requires SIPs to include a program to provide
for the enforcement of SIP measures. The implementing regulation for
this section is found at 40 CFR 51.111(a) and requires control
strategies to include a description of enforcement methods including
(1) procedures for monitoring compliance with each of the selected
control measures, (2) procedures for handling violations, and (3) the
designation of the agency responsible for enforcement.
The principle control measures in the plan are MCESD's Rules 310
and 310.01 and the BMP General Permit. Procedures for monitoring
compliance (i.e., the inspection strategy) with these rules are
described in Maricopa County's commitments and the BMP TSD. See
Maricopa County commitment, 1999 Revised Measure 6 and BMP TSD, pp 33-
34.
Based on the review of MCESD's enforcement procedures, we propose
to find that the MAG plan adequately provides for the enforcement of
the principle measures relied on for attainment and that the plan
includes an adequate description of enforcement methods as required by
our regulations.
Section 110(a)(2)(E)(iii) requires SIPs to include necessary
assurances that where a State has relied on a local or regional
government, agency or instrumentality for the implementation of any
plan provision, the State has responsibility for ensuring adequate
implementation of the such plan provision.
We have previously found that Arizona law includes the necessary
assurances that where a State has relied on a local or regional
government, agency or instrumentality for the implementation of any
plan provision, the State has responsibility for ensuring adequate
implementation of the such plan provision. 60 FR 18010, 18019 (April
10, 1995).
[[Page 50281]]
V. CAA Requirements for BACM and Attainment Date Extension and
EPA's Guidance on Meeting These Requirements
A. Implementation of Best Available Control Measures
Under section 189(b)(2), serious area PM-10 plans must provide
assurances that BACM will be implemented in the area no later than four
years after the area is reclassified as serious. For Phoenix, the BACM
implementation deadline was June 10, 2000.
The Act does not define what level of control constitutes a BACM-
level of control. In guidance, we have defined it to be, among other
things, the maximum degree of emission reduction achievable from a
source or source category which is determined on a case-by-case basis,
considering energy, economic and environmental impacts. Addendum at
42010. This level of control is dependent on the deadline by which BACM
must be implemented.\50\
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\50\ We have long held that an otherwise available measure is
reasonable and thus not an available measure if it cannot be
implemented on a schedule that will advance the attainment date.
See, for example, 57 FR 13498, 13560 (April 16, 1992). See, also
Delaney v. EPA 898 F.2d 695 (9th Cir. 1990) which required the
adoption of ``all available control measures'' to attain ``as soon
as possible'' and not simply all available control measures. The
most clear example of this is a measure that cannot be implemented
until after the applicable attainment date.
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We also considered a BACM-level control as going beyond existing
RACM-level controls, such as expanding use of RACM (e.g, paving more
miles of unpaved roads). Addendum at 42013. Additionally, we believe
that BACM should emphasize prevention rather than remediation (e.g.,
preventing track out at construction sites rather than simply requiring
clean up of tracked-out dirt). Addendum at 42013.
BACM is a best available control measure. A control measure is a
combination of a statement of applicability and the control
requirement, that is, what sources in the category are subject to the
measure and what the measure require the sources to do to reduce
emissions.\51\ Both these elements must be specified before the
measure's level of control (i.e., its stringency) can be determined,
thus in setting out a BACM, a state must specify both the measure's
control requirement and its applicability. The control requirement
alone is not sufficient.
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\51\ An example: a measure requires all unpaved roads with ADT
over 150 be stabilized by either paving, graveling, or treating with
chemical stabilizers. The control requirement here is ``Stabilize
using one of these three methods: paving, graveling, or chemical
stabilization'' and the applicability is ``all unpaved roads with
ADT over 150.''
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BACM must be applied to each significant (i.e., non-de minimis)
source category. Addendum at 42011. In guidance, we have established a
presumption that a ``significant'' source category is one that
contributes 5 µg/m\3\ or more of PM-10 to a location of 24-hour
violation. Addendum at 42011. However, whether the threshold should be
lower than this in any particular area depends upon the specific facts
of that area's nonattainment problem. Specifically, in areas that are
demonstrating attainment by December 31, 2001, it depends on whether
requiring the application of BACM on source categories below a proposed
de minimis level would meaningfully expedite attainment. In areas that
are claiming the impracticability of attainment by December 31, 2001,
it depends upon whether requiring the application of BACM on source
categories below a proposed de minimis level would make the difference
between attainment and nonattainment by the serious area deadline of
December 31, 2001.\52\
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\52\ This principle is best illustrated by an example: In Area
A, attainment of the 24-hour standard by December 31, 2001 requires
that PM-10 ambient levels at exceeding locations be reduced by 40
µg/m\3\ to 150 µg/m\3\. After application of BACM to
all source categories above the proposed de minimis level, PM-10
levels are reduced by 32 µg/m\3\. BACM on the proposed de
minimis source categories would reduce levels by a further 3
µg/m\3\, but still leaves ambient levels 5 µg/m\3\
short of the reduction needed to show attainment. Since application
of BACM to the proposed de minimis source categories still leaves
ambient levels above the attainment level of 150 µg/m\3\,
the proposed de minimis level is appropriate.
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The recent decision by the Ninth Circuit Court of Appeals in Ober
v. Whitman 243 F.3d 1190 (9th Cir. 2001) (Ober II) supports the use of
a de minimis exemption in BACM analyses. Ober II was a challenge to our
1998 PM-10 moderate area FIP for the Phoenix area in which we exempted
from the RACM requirement, source categories with de minimis impacts on
PM-10 levels. In the FIP, we established a de minimis threshold of 1
µg/m\3\ for the annual standard and 5 µg/m\3\ for the
24-hour standard, borrowing these thresholds from our new source review
program for attainment areas to as a starting point in the de minimis
analysis. In evaluating the appropriateness of these thresholds, we
showed that they did not eliminate controls that would make the
difference between attainment and nonattainment by the applicable
attainment deadline, and therefore were the appropriate thresholds. See
63 FR 41326, 41330 (August 3, 1998).
In its ruling, the court held that we have the power to make de
minimis exemptions to control requirements under the Clean Air Act and
that our use of the de minimis levels from the NSR program was
appropriate. Ober II at 1195 and 1197. In addition, the court
determined that it was appropriate for us to use, as a criterion for
identifying de minimis sources, whether controls on the sources would
result in attainment by the attainment deadline. Ober II at 1198. Ober
II dealt with a de minimis exemption from the RACM requirement, but its
reasoning applies equally to the BACM requirement.
We have outlined in our guidance a multi-step process for
identifying BACM. Addendum at 42010-42014. The steps are:
1. develop a detailed emissions inventory of PM-10 sources and
source categories,
2. model to evaluate the impact on PM-10 concentrations over the
standards of the various sources and source categories to determine
which are significant,
3. identify potential BACM for significant source categories
including their technological feasibility, costs, and energy and
environmental impacts when it bears on the BACM determination, and
4. provide for the implementation of the BACM or provide a reasoned
justification for rejecting any potential BACM.
B. Extension of the Attainment Date Beyond 2001
Section 188(e) of the Act allows us to extend the attainment date
for a serious area for up to five years beyond 2001 if attainment by
2001 is impracticable. However, before we may grant an extension of the
attainment date, the State must first:
1. apply to us for an extension of the PM-10 attainment date beyond
2001,
2. demonstrate that attainment by 2001 is impracticable,
3. have complied with all requirements and commitments applying to
the area in its implementation plan,
4. demonstrate to our satisfaction that its serious area plan
includes the most stringent measures that are included in the
implementation plan of any state and/or are achieved in practice in any
state and are feasible for the area, and
5. submit a demonstration of attainment by the most expeditious
alternative date practicable.
6. the technological and economic feasibility of various control
measures.
We may grant only one extension for an area and that extension
cannot be for
[[Page 50282]]
more than 5 years after 2001; that is, the extended attainment date can
be no later than December 31, 2006. CAA section 188(e).
We first presented our preliminary interpretation of the attainment
date extension provision in our proposed approval of the annual
standard provisions in the MAG plan. See 66 FR 19992, 19967. Based on
comments we received on it during that proposal's comment period, we
have clarified certain aspects of the policy but have made no
substantive changes to it. We will provide our full response to
comments received on the annual standard proposal when we take final
action.
This interpretation is our preliminary view of the section 188(e)
requirements and we again request comment on it. We emphasize that
these are our preliminary views and they are subject to modification as
we gain more experience reviewing extension requests from other areas.
In the following sections we discuss the five requirements a State
must meet before we can consider granting an attainment date extension.
1. Apply for an Attainment Date Extension
Under CAA section 188(e), a State must apply for an extension of
the attainment deadline. The request should be accompanied by the SIP
submittal containing the most expeditious alternative attainment date
demonstration required by CAA section 189(b)(1)(A)(ii). The state must
be provided the public with reasonable notice and a hearing on the
request before it is sent to EPA.
Extension requests are not SIP submittals per se \53\ and are
therefore not subject to the requirements of the Clean Air Act and our
regulations for public notice and hearing on SIP revisions. However,
because they can greatly affect the content and ultimate approvability
of a serious area PM-10 SIP, we believe a state must give the public an
opportunity, consistent with the requirements for SIP revisions, to
comment on an extension request prior to submitting it to us.
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\53\ This is clear from the wording of section 188(e) which
makes a distinction between the application for an extension and the
SIP revision that must accompany it: ``at the time of the such
application, the State must submit a revision to the implementation
plan that includes a demonstration of attainment by the most
expeditious alternative date practicable.'' This attainment
demonstration is the one required by section 189(b)(1)(A)(ii).
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2. Demonstrate That Attainment by 2001 is Impracticable
In order to demonstrate impracticability, the plan must show that
the implementation of BACM on significant (that is, non-de minimis)
source categories will not bring the area into attainment by December
31, 2001. In serious areas, BACM is required to be in place in advance
of the 2001 attainment date; therefore, we believe that it is
reasonable to interpret the Act to require that a state provide at
least for the implementation of BACM on significant source categories
before it can claim impracticability of attainment by 2001.\54\ This
interpretation parallels our interpretation of the impracticability
option for moderate PM-10 nonattainment areas in section 189(a)(1)(B).
In moderate areas, RACM was required before a moderate area plan could
claim impracticability of attainment by 1994, the moderate area
attainment date. See 57 FR 13498, 13544 (April 16, 1992). The Ober II
court found this approach reasonable. Ober II at 1198.
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\54\ As described in the section on the BACM requirement, if
applying BACM-level controls to one or more of the proposed de
minimis source categories would result in attainment by December 31,
2001, then those categories are not de minimis (i.e., they are
significant) and must have BACM applied to them. Therefore, states
cannot use the de minimis exemption to BACM to avoid applying
controls that would result in attainment by 2001.
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The statutory provision for demonstrating impracticability requires
that the demonstration be based on air quality modeling. See section
189(b)(1)(A). We have established minimum requirements for air quality
modeling. See discussion on air quality modeling later in this TSD.
3. Have Complied With all Requirements and Commitments in its
Implementation Plan
We interpret this criterion to mean that the state has implemented
the emission reducing measures in the plan revisions it has submitted
to address the CAA requirements in sections 172 and 189 for PM-10
nonattainment areas.
The purpose of this criterion is to assure that a state is not
receiving additional time to attain because it failed to implement
already-adopted or already-committed-to control measures. Given this
purpose, we believe our review under this criterion should be limited
to the implementation status of control measures from earlier PM-10
plans and not be an expansive review of the implementation status of
every provision in submitted implementation plans, whether or not it is
an emission reducing measure.
We read this provision not to require the area to have a fully
approved plan that meets the CAA's requirements for moderate areas. We
base this reading on the plain language of section 188(e) which
requires the state to comply with all requirements and commitments
pertaining to that area in the implementation plan but does not require
that the state comply with all requirements pertaining to the area in
the Act. For the same reason, we also read this provision not to bar an
extension if all or part of an area's moderate area plan is disapproved
or has been promulgated as a FIP or if the area has failed to meet a
RFP milestone.
Part of determining whether a state has implemented its commitments
and requirements in earlier plans is assessing whether the state
retains the legal authority for them and is funding, staffing, and
enforcing them at the level assumed or committed to in those plans.
Thus any determination that the state has met its commitments and
requirements in earlier plans is also a finding that it has retained
its legal authority and has met its commitments regarding enforcement,
funding, and staffing.
4. Demonstrate the Inclusion of the Most Stringent Measures
The fourth extension criterion requires the State to ``demonstrate
to the satisfaction of the Administrator that the plan for the area
includes the most stringent measures that are included in the
implementation plan of any State, or are achieved in practice in any
State, and can be feasibly be implemented in the area.'' CAA section
188(e).
The requirement for most stringent measures (MSM) is similar to the
requirement for BACM. We define a BACM-level of control to be, among
other things, the maximum degree of emission reduction achievable from
a source or source category which is determined on a case by case basis
considering energy, economic and environmental impacts. Addendum at
42010. The Act establishes the deadline for implementing BACM as four
years after an area's reclassification to serious. CAA section
189(b)(1)(A).
We propose to define a ``most stringent measure'' level of control
in a similar manner: the maximum degree of emission reduction that has
been required or achieved from a source or source category in other
SIPs or in practice in other states and can be feasibly implemented in
the area. A MSM then is a control measure that delivers this level of
control.
The Act does not specify an implementation deadline for MSM.
Because the clear intent of section 188(e) is to minimize the length of
any attainment date extension, we propose that the implementation of
MSM should be as expeditiously as practicable.
[[Page 50283]]
Given this similarity between the BACM requirement and the MSM
requirement, we believe that determining MSM should follow a process
similar to determining BACM, but with one additional step, to compare
the potentially most stringent measure against the measures already
adopted in the area to determine if the existing measures are most
stringent:
1. Develop a detailed emissions inventory of PM-10 sources and
source categories,
2. Model to evaluate the impact on PM-10 concentrations over the
standards of the various source categories to determine which are
significant for the purposes of adopting MSM,
3. Identify the potentially most stringent measures in other
implementation plans or used in practice in other states for each
significant source category and for each measure determine their
technological and economic feasibility for the area as necessary,
4. Compare the potentially most stringent measures for each
significant source category against the measures, if any, already
adopted for that source category, and
5. Provide for the adoption of any MSM that is more stringent than
existing similar local measures and provide for implementation as
expeditiously as practicable or, in lieu of providing for adoption,
provide a reasoned justification for rejecting the potential MSM, i.e.,
why such measures cannot be feasibly implemented in the area.
The MSM provision only requires that a state consider the best
controls from elsewhere in the country for implementation in the area
requesting an attainment date extension. It looks to see--and the
results are completely dependent on--how well other areas have
controlled their PM-10 sources. If other areas have not controlled a
particular source or source category well, then the resulting level of
control from the MSM will not be the maximum feasible level of control
for that source or source category in the local area. Even if they have
controlled them well, the resulting level of control may still not be
the maximum feasible level because local conditions may allow a higher
degree of control than has been achieved elsewhere.
The MSM provision does not require a state to consider if local
sources or source categories can be controlled at a level greater than
the most stringent level from other areas. In other words, it does not
require states to determine and adopt the maximum feasible level of
control that could be applied to a source or a source category given
local conditions and the additional implementation time afforded by an
extension.
In considering the MSM provision, the inclination is to assume that
there are always better controls in other areas than there are in the
local area. This assumption is unwarranted, especially for areas that
have already gone through the process of identifying and adopting BACM
for their significant sources in order to meet the section 189(b)(1)(B)
requirement. These areas are likely to have already evaluated the best
controls from other areas and either adopted them as BACM or rejected
them as not feasible for their area. As a result, the likelihood of
finding substantial new controls during a MSM evaluation in one of
these areas is low.\55\
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\55\ There is also an inclination to assume that the MSM
requirement is the provision in section 188(e) that implements the
Act's general strategy of offsetting longer attainment time frames
with more stringer control and therefore, the MSM requirement must
be interpreted to result in the adoption of measures more stringent
than BACM. We believe, however, that this offsetting function is
actually served by the CAA section 189(b)(i)(A)(ii) requirement for
PM-10 plans to demonstrate attainment by the most expeditious date
practicable, if attainment by 2001 is impracticable. Because we are
required to grant the shortest possible extension, a state must
demonstrate that it has adopted the set of control measures that
will result in the most expeditious date practicable for
attainement. This requirement may very well require that a state
adopt controls that go beyond the most stringent measures adopted or
implemented elsewhere.
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De Minimis Thresholds. What constitutes a de minimis source
category for BACM is dependent upon the specific facts of the
nonattainment problem under consideration. In particular, it depends
upon whether requiring the application of BACM for such sources would
make the difference between attainment and nonattainment by the serious
area deadline. We propose to use a similar approach for judging what
constitutes a de minimis source category for MSM but instead of the
attainment/nonattainment test, we propose to use the test of whether
MSM controls on the de minimis sources would result in more expeditious
attainment.
We would not review an MSM analysis in a plan if the plan did not
demonstrate expeditious attainment since one prerequisite for granting
an extension request is that the plan demonstrate attainment.
Therefore, any de minimis standard for MSM that relied on the
difference between attainment and nonattainment would be meaningless
because no additional controls are needed for attainment beyond those
already in the plan. Our responsibility under section 188(e), however,
is to grant the shortest practicable extension of the attainment date
by assuring the plan provides for attainment as expeditiously as
practicable. Thus, one means of determining an appropriate de minimis
level is to determine if applying MSM to the proposed de minimis source
categories would meaningfully expedite attainment. If it did, then the
de minimis level is too high, and if it did not, then the de minimis
level is appropriate.
Like the RACM and BACM requirements, there is no explicit provision
in the Act prohibiting an exemption from the MSM requirement for de
minimis sources of PM-10 pollution. We are using here the same
principles for determining when a source is considered de minimis under
the MSM requirement that we used for the RACM requirement that the Ober
II court upheld and thus we have constructed the de minimis exemption
for the MSM requirement to prevent states from eliminating any controls
on sources or source categories that alone or together would result in
more expeditious attainment of the PM-10 standards.
Technological feasibility. In the MSM analysis, a state must
evaluate the application of controls from elsewhere to sources in its
own area. In many cases, these sources are already subject to local
control measures. In these situations, part of determining if a control
is technologically feasible is determining if the new control can be
integrated with the existing controls without reducing or delaying the
emission reductions from the existing control. If it cannot, then we
would not, in general, consider the measure to be technologically
feasible for the area unless the emission benefit of the new measure is
substantially greater than the existing measure.
Economic feasibility. Because cost is rarely used to justify
rejection of a measure in the MAG plan, we will not attempt to
establish a general guide for evaluating when a measure is economically
infeasible but instead will address the issue on a case-by-case basis
as needed.
Judging stringency. The stringency of a control measure is
determined primarily by a combination of its applicability and its
control requirement, that is, who in the source category is subject to
the measure and what does the measure requires them to do to reduce
emissions. When we use the term ``measure'' in the context of the MSM
requirement, we are referring to this combination; we are not referring
to
[[Page 50284]]
just the control requirement or to individual methods of control.
The approach we propose to use in evaluating the selection of the
most stringent among multiple measures, i.e., evaluating the
determination of when one control measure is more stringent than
another, is:
1. If there is only a single measure applicable to a source
category then we will compare the measures directly. If there are
multiple control measures with diverse controls requirements applicable
to a source category (e.g., tailpipe emissions are controlled through
fuels, emission standards, inspection and maintenance programs, and
transportation control measures) then we will compare measures with
similar control requirements against one another. If several measures
apply the same or very similar control requirements to a source
category, that is they have the same control requirement but different
applicablities (e.g., MCESD Rule 310.01 and City and County commitments
all require similar controls on unpaved roads), then will use the
collective stringency of all the measures in the stringency analysis.
2. We will review all the provisions of a rule that apply to a
specific type of source (e.g., all the rule provision that apply to
vacant lots) as an inseparable measure. As discussed above a rule's
stringency is defined by a combination of its applicability and control
requirements (as they apply to a single type of source). They are not
separable elements that can be compared in isolation to another
rule.\56\
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\56\ For example, South Coast Rule 403 covers vacant lots,
construction sites, and agriculture among other fugitive dust
sources. MCESD's Rule 310.01 covers vacant lots and Rule 310 covers
construction sites. The Arizona BMP rule covers agricultural
sources. Under this test we would evaluate Rule 403's provisions for
vacant lots against Rule 310.01 provisions for vacant lots; Rule
403's provisions for construction sites against Rule 310's provision
for construction sites; Rule 403's provisions for agricultural
sources against the BMP rule's ones.
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3. In a MSM analysis, a measure's stringency should be determined
assuming that it is appropriately adopted, implemented and enforced.
Thus, we will not use a measure's implementation mechanisms (e.g., rule
versus commitment), funding level, compliance schedule, test method,
resources available for enforcement, or other similar items as criteria
for judging relative stringency.\57\
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\57\ However, once a State determines a measure is a feasible
most stringent measure, it must convert the measure into a legally
enforceable form and provide the necessary level of resources, etc.
to ensure its implementation.
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A state may determine which measure or measures are most stringent
either qualitatively or quantitatively. It is the state's
responsibility, however, to assure that any determination is well
documented and persuasive.
Once a state has identified a potential most stringent measure, it
must provide for the adoption of any MSM that is more stringent than
existing measures and provide for implementation as expeditiously as
practicable or, in lieu of providing for adoption, provide a reasoned
justification for rejecting the potential MSM, i.e., why such measures
cannot be feasibly implemented in the area.
Finally, we address how we view the ``to the satisfaction of the
Administrator'' qualifier on the requirement that the State demonstrate
that its plan includes the most stringent measures. The presence and
wording of this qualifier indicates that Congress granted us
considerable discretion in determining whether a plan in fact provides
for MSM. Under the terms of section 188(e), we believe that we can
still accept an MSM demonstration even if it falls short of having
every MSM possible. To intuit the limits of this discretion, we again
look to the overall intent of section 188(e) that we grant as short an
extension as practicable and to how we have interpreted the CAA's other
general control requirements, RACM and BACM.
In concrete terms, this means that when judging the overall
adequacy of the MSM demonstration, we will give more weight to a
failure to include MSM for source categories that contribute the most
to the PM-10 problem and to the failure to include measures that could
provide for more expeditious attainment and less weight to those
measures for source categories that contribute little to the PM-10
problem and would not expedite attainment.
5. Demonstrate Attainment by the Most Expeditious Alternative Date
Practicable.
Section 189(b)(1)(A) requires that a serious area plan demonstrate
attainment by the most expeditious date practicable using air quality
modeling after December 31, 2001. This demonstration is the final
criterion that must be met before we may grant an extension request.
There are two parts to reviewing a modeled attainment
demonstration: evaluating the technical adequacy of the modeling
itself, and evaluating the control measures that are relied on to
demonstrate attainment.
We have established technical requirements for modeling PM-10 in
SIP attainment demonstrations. Please see discussion later in this TSD
on modeling requirements for PM-10 SIPs.
In order to evaluate the control measures relied on in the
attainment demonstration to determine if:
1. We have approved it into the SIP or the State has submitted it
to us for approval into the SIP.
2. It is enforceable under our SIP-enforceability standards or
qualifies to be credited under our mobile source voluntary measures
policy.\58\
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\58\ Memorandum, Richard D. Wilson, Acting Assistant
Administrator for Air and Radiation, to EPA Regional Administrators,
1-10, ``Guidance on Incorporating Voluntary Mobile Source Reduction
Programs in State Implementation Plans (SIPs),'' October 24, 1997.
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3. The plan provides reasonable assurances, including funding and
other resource commitments, that it will be implemented and enforced.
4. It will be implemented on the most expedient schedule
practicable.
5. The emission reductions credited to it are reasonable and
consistent with the implementation resources and schedule, and for any
reductions coming from mobile source voluntary measures, that they do
not collectively exceed 3 percent of the total reductions needed for
attainment.\59\
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\59\ Ibid., page 5.
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Our determination of whether the plan provides for attainment by
the most expeditious date practicable will depend on whether we find
that the plan provides for appropriate BACM, MSM, and any other
technologically and economically feasible measures that will result in
attainment as expeditiously as practicable and that these measures are
implemented on an expeditious schedule.
Please see section 3 of the EPA TSD for additional discussion of
our proposed interpretation of the extension requirements.
VI. Administrative Requirements
Under Executive Order 12866 (58 FR 51735, October 4, 1993), this
proposed action is not a ``significant regulatory action'' and
therefore is not subject to review by the Office of Management and
Budget. For this reason, this proposed action is also not subject to
Executive Order 32111, ``Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use'' (66 FR
28355, May 22, 2001). This proposed action merely approves state law as
meeting federal requirements and imposes no additional requirements
beyond those imposed by state law. Accordingly, the Administrator
certifies that this proposed rule will not have a significant economic
impact on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.). Because this rule
[[Page 50285]]
proposes to approve pre-existing requirements under state law and does
not impose any additional enforceable duty beyond that required by
state law, it does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Public Law 104-4). This rule also does not
have a substantial direct effect on one or more Indian tribes, on the
relationship between the Federal Government and Indian tribes, or on
the distribution of power and responsibilities between the Federal
Government and Indian tribes, as specified by Executive Order 13175 (65
FR 67249, November 9, 2000), nor will it have substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government, as specified
in Executive Order 13132 (64 FR 43255, August 10, 1999), because it
merely approves a state rule implementing a federal standard, and does
not alter the relationship or the distribution of power and
responsibilities established in the Clean Air Act. This proposed rule
also is not subject to Executive Order 13045 (62 FR 19885, April 23,
1997), because it is not economically significant.
In reviewing SIP submissions, EPA's role is to approve state
choices, provided that they meet the criteria of the Clean Air Act. In
this context, in the absence of a prior existing requirement for the
State to use voluntary consensus standards (VCS), EPA has no authority
to disapprove a SIP submission for failure to use VCS. It would thus be
inconsistent with applicable law for EPA, when it reviews a SIP
submission, to use VCS in place of a SIP submission that otherwise
satisfies the provisions of the Clean Air Act. Thus, the requirements
of section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (15 U.S.C. 272 note) do not apply. As required by section 3
of Executive Order 12988 (61 FR 4729, February 7, 1996), in issuing
this proposed rule, EPA has taken the necessary steps to eliminate
drafting errors and ambiguity, minimize potential litigation, and
provide a clear legal standard for affected conduct. EPA has complied
with Executive Order 12630 (53 FR 8859, March 15, 1988) by examining
the takings implications of the rule in accordance with the ``Attorney
General's Supplemental Guidelines for the Evaluation of Risk and
Avoidance of Unanticipated Takings'' issued under the executive order.
This proposed rule does not impose an information collection burden
under the provisions of the Paperwork Reduction Act of 1995 (44 U.S.C.
3501 et seq.).
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Intergovernmental
relations, Particulate matter, Reporting and recordkeeping
requirements.
Authority: 42 U.S.C. 7401 et seq.
Dated: September 14, 2001.
Mike Schulz,
Acting Regional Administrator, Region IX.
[FR Doc. 01-24203 Filed 10-1-01; 8:45 am]
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