Approval and Promulgation of Implementation Plans; Las Vegas Valley Carbon Monoxide Attainment Plan

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

[Federal Register: May 9, 2006 (Volume 71, Number 89)]
[Proposed Rules]
[Page 26910-26918]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr09my06-27]

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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R09-OAR-2006-0322; FRL-8167-9]

Approval and Promulgation of Implementation Plans; Las Vegas
Valley Carbon Monoxide Attainment Plan

AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.

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SUMMARY: EPA proposes to approve a revised attainment plan for the Las
Vegas Valley carbon monoxide nonattainment area on the condition that
Clark County and the State of Nevada withdraw the 2030 motor vehicle
emission budget, or, in the alternative, to disapprove the plan. This
plan has been submitted to the Agency by the State of Nevada as a
revision to the Nevada state implementation plan. The revised
attainment plan includes revised base year and future year emissions
inventories and a revised demonstration of continued attainment of the
carbon monoxide national ambient air quality standard in Las Vegas
Valley through 2030 based on the most recent emissions models and
planning assumptions and establishes new motor vehicle emissions
budgets. EPA is proposing this action under section 110(k) of the Clean
Air Act, which obligates the Agency to take action on State submittals
of revisions to state implementation plans. The intended effect of this
proposed approval action is to update the carbon monoxide motor vehicle
emissions budgets in the Las Vegas area and thereby make them available
for the purposes of transportation conformity, and the intended effect
of this proposed disapproval action is to retain the previously-
approved budgets.

DATES: Any comments on this proposal must arrive by June 8, 2006.
Public comments on this action are requested and will be considered
before taking final action.

ADDRESSES: Submit comments, identified by docket number EPA-R09-OAR-
2006-0322, by one of the following methods:
1. http://www.regulations.gov: Follow the on-line instructions for
submitting comments.
2. E-mail: oconnor.karina@epa.gov.
3. Mail or deliver: Karina O'Connor (AIR-2), U.S. Environmental
Protection Agency Region IX, 75 Hawthorne Street, San Francisco, CA
94105-3901.
Instructions: Direct your comments to EPA-R09-OAR-2006-0322. EPA's
policy is that all comments received will be included in the public
docket without change and may be made available online at http://
www.regulations.gov, including any personal information provided,
unless the comment includes information claimed to be Confidential
Business Information (CBI) or other information whose disclosure is
restricted by statute. Do not submit information that you consider to
be CBI or otherwise protected through http://www.regulations.gov
or e-mail. The http://www.regulations.gov, Web site is an ``anonymous
access'' system, which means EPA will not know your identity or contact
information unless you provide it in the body of your comment. If you send
an e-mail comment directly to EPA without going through http://
www.regulations.gov, your e-mail address will be automatically
captured and included as part of the comment that is placed in the public
docket and made available on the Internet. If you submit an electronic
comment, EPA recommends that you include your name and other contact
information in the body of your comment and with any disk or CD-ROM you
submit. If EPA cannot read your comment due to technical difficulties
and cannot contact you for clarification, EPA may not be able to
consider your comment. Electronic files should avoid the use of special
characters, any form of encryption, and be free of any defects or viruses.
Docket: All documents in the electronic docket are listed in the
http://www.regulations.gov index. Although listed in the index,
some information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other information,
such as copyrighted material, will be publicly available only in hard
copy. Publicly available docket materials are available either
electronically in http://www.regulations.gov or in hard copy at
EPA Region IX, 75 Hawthorne Street, San Francisco, California. To inspect
the hard copy materials, please schedule an appointment during normal
business hours with the contact listed in the FOR FURTHER INFORMATION
CONTACT section.

FOR FURTHER INFORMATION CONTACT: Karina O'Connor, EPA Region IX,
telephone number: (775) 833-1276; fax number: (775) 833-1276; e-mail
address: oconnor.karina@epa.gov.

SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us'' and
``our'' refer to EPA.

Table of Contents

I. Summary of Action
II. Introduction
A. What Is the Purpose of this Proposed Rulemaking?
B. What Did the State Submit To EPA?
C. What Is a SIP and How Is it Revised From Time to Time?
D. What Is the Background of Today's Action?
E. What Are MOBILE6 And MOBILE6.2?
F. What Is the Current Status of CO Levels in Las Vegas Valley
and how do the Levels Compare With the Federal Standards?
III. Review of the Las Vegas Valley 2005 CO Plan Submittal
A. What Is the Purpose and Content of Nevada's Submittal?
B. How Is EPA Evaluating This Submittal?
C. How Have Emissions of Carbon Monoxide in Las Vegas Valley Changed?
D. How Has the Attainment Demonstration Changed?
E. Are Las Vegas Valley's Motor Vehicle Emissions Budgets Approvable?
F. How Does This Action Affect Transportation Conformity?
IV. Proposed Action and Request for Public Comment
V. Statutory and Executive Order Reviews

I. Summary of Action

Under section 110(k) of the Clean Air Act (CAA or Act), EPA
proposes to approve a revised attainment plan for the Las Vegas Valley
carbon monoxide (CO) nonattainment area on the condition that Clark
County and the State of Nevada withdraw the 2030 motor vehicle emission
budget, or, in the alternative, to disapprove the plan.
This plan has been submitted to EPA by the Nevada Division of
Environmental Protection (NDEP) as a revision to the Nevada state
implementation plan (SIP). The revised attainment plan includes revised
base year and future year emissions inventories and a revised
demonstration of continued attainment of the carbon monoxide national
ambient air quality standard in Las Vegas Valley through 2030 based on
the most recent emissions models and planning assumptions and
establishes new motor vehicle emissions budgets. The intended effect of
this proposed approval action is to update the carbon monoxide motor
vehicle emissions

[[Page 26911]]

budgets in the Las Vegas area and thereby make them available for the
purposes of transportation conformity, and the intended effect of this
proposed disapproval action is to retain the previously-approved
budgets. The currently approved attainment plan did not include 2030
budgets, therefore we do not need 2030 budgets to be able to approve
the remaining budgets in the revised plan.

II. Introduction

A. What Is the Purpose of this Proposed Rulemaking?

The purpose of this proposed rulemaking is to present our
evaluation and conclusions with respect to a submittal of a revision to
the Nevada SIP, identified below, that includes a revised attainment
plan for the Las Vegas CO nonattainment area. The revised plan includes
updated emissions inventories and dispersion modeling in support of new
motor vehicle emissions budgets.

B. What Did the State Submit to EPA?

Under a letter dated February 14, 2006, NDEP submitted the Carbon
Monoxide State Implementation Plan Revision, Las Vegas Valley
Nonattainment Area, Clark County, Nevada (October 2005) (``2005 CO
plan''), to EPA as a revision to the Nevada SIP following the plan's
adoption by the Clark County Board of Commissioners on October 4, 2005.
Prepared by the Clark County Department of Air Quality and
Environmental Management (DAQEM), the 2005 CO plan includes a revised
emissions inventory, a revised modeling demonstration of continued
attainment, and revised motor vehicle emissions budgets. The
inventories and modeling demonstration included in the 2005 CO plan
relate to analysis years 1996, 2006, 2010, 2015, 2020 and 2030. The
plan allocates almost all of the estimated safety margins \1\ in years
2006, 2010, 2015, 2020, and 2030 to the on-road motor vehicle emissions
category.
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\1\ The term ``safety margin'' refers to the amount by which the
total projected emissions from all sources of a given pollutant are
less than the total emissions that would satisfy the applicable
requirement for reasonable further progress, attainment or
maintenance. See 40 CFR 93.101. The 2005 CO plan also allocates a
small portion of the safety margins to certain point sources.
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Also submitted by NDEP on February 14, 2006 is a report entitled,
``Supplement to the Carbon Monoxide State Implementation Plan
Revision,'' which was prepared by DAQEM in response to comments raised
by EPA subsequent to the Clark County Board of Commissioners' adoption
of the 2005 CO plan. This supplemental report presents an air quality
trends analysis in further support for the plan's forecast of continued
attainment through 2030 with the plan's proposed motor vehicle
emissions budgets.

C. What is a SIP and How Is it Revised From Time to Time?

The Clean Air Act requires States to attain and maintain ambient
air quality equal to or better than standards that provide an adequate
margin of safety for public health and welfare. These ambient air
quality standards are established by EPA and are known as the National
Ambient Air Quality Standards (NAAQS). Carbon monoxide (CO) is one of
the pollutants for which EPA has established NAAQS.
The State's plan for attaining and maintaining the NAAQS are
outlined in the SIP for that state. The SIP is a planning document
that, when implemented, is designed to ensure the achievement of the
NAAQS. Each State currently has a SIP in place, and the Act requires
that States make SIP revisions periodically as necessary to provide
continued compliance with the standards. The State of Nevada's SIP is
identified at title 40, part 52, subpart DD of the Code of Federal
Regulations (40 CFR part 52, subpart DD).
SIPs may include, among other things, the following: (1) An
inventory of emission sources; (2) statutes and regulations adopted by
the State legislature and executive agencies; (3) air quality analyses
that include demonstrations that adequate controls are in place to meet
the NAAQS; and (4) contingency measures to be undertaken if an area
fails to attain the standard or make reasonable progress toward
attainment by the required date. The State must make the SIP available
for public review and comment through a public hearing before it is
adopted by the State and submitted to EPA by the Governor or his
appointed designee. When EPA takes Federal action to approve the SIP
submittal, the rules and regulations become federally enforceable.
For an area designated as nonattainment for a given NAAQS, the
State first submits a plan with emissions reduction measures to bring
the area into attainment. Once the area has attained the standard based
on monitored air quality, the State then submits a redesignation
request to attainment and a maintenance plan demonstrating that the
area will continue to maintain the standard for at least 10 years after
the redesignation into attainment.

D. What Is the Background of Today's Action?

Based on CO monitoring data from the mid-1970's, EPA designated Las
Vegas Valley \2\ as a CO nonattainment area under the Clean Air Act, as
amended in 1977. See 43 FR 8962, 9012 (March 3, 1978). In response,
Clark County and the State of Nevada adopted and implemented various
air quality plans and programs, including a vehicle inspection and
maintenance (I/M) program, to reduce CO levels in Las Vegas Valley, but
the CO NAAQS was not attained by the then-applicable 1987 attainment date.
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\2\ The boundaries of the Las Vegas Valley CO nonattainment area
are defined by reference to State hydrographic area #212,
which covers the central portion of Clark County. See 40 CFR 81.329.
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The Clean Air Act was significantly amended by Congress in 1990 to
establish new attainment dates and planning and control requirements
for areas that had failed to attain the NAAQS under the 1977
Amendments. Under the 1990 Amended Act, Las Vegas Valley was classified
as a ``moderate'' nonattainment area for CO with a new attainment date
of December 31, 1995 and subject to the specific requirements for such
areas. EPA later extended the attainment date to December 31, 1996, but
given monitoring data from that period showing continued CO NAAQS
violations, EPA reclassified Las Vegas Valley in 1997 as a ``serious''
CO nonattainment area with an attainment date of December 31, 2000 and
subject to the additional requirements applicable to such areas. See 62
FR 51604 (October 2, 1997).
In response to the ``moderate'', and then ``serious,''
nonattainment classification and related CAA requirements, Clark County
and the State of Nevada adopted and implemented new air quality plans
and programs, including wintertime gasoline specifications for oxygen
content and Reid Vapor Pressure(RVP), enhancement to the vehicle I/M
program and a ``serious'' area attainment plan, the Carbon Monoxide
State Implementation Plan, Las Vegas Valley Nonattainment Area, Clark
County, Nevada (August 2000) (``2000 CO plan''). The 2000 CO plan
included a base year (1996) emission inventory, future-year emissions
projections, an attainment demonstration, and additional control
measures, including additional wintertime gasoline specifications for
sulfur and aromatics (referred to as ``cleaner burning gasoline''), an
alternative fuels program for government vehicles, and a

[[Page 26912]]

transportation control measure program. The plan also established motor
vehicle emissions budgets and provided modeling documentation showing
that the CO standard would continue to be attained beyond the
attainment deadline of 2000 through the 2020 analysis year. In 1998, we
approved the wintertime gasoline specification for oxygen content (i.e.
oxygenated fuel program) (64 FR 29573, June 2, 1999), and in 2004, we
approved the revised vehicle I/M program, the wintertime gasoline
specification for RVP, and all of the elements of the 2000 CO plan
(except for the contingency provisions \3\, including the new control
measures (e.g., cleaner burning gasoline rule), emissions inventories,
attainment demonstration, and motor vehicle emissions budgets (69 FR
56351, September 21, 2004).
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\3\ Note that the contingency measure requirement was removed
when EPA made a finding of attainment in June 2005 (See 70 FR 31353).
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The 2000 CO plan established motor vehicle emission budgets for
years 2000, 2010, and 2020. These budgets were developed using
MOBILE5b, which was the latest EPA-approved motor vehicle emission
factor model at that time. EPA officially released a new version of
motor vehicle emissions model, MOBILE6, on January 29, 2002 (67 FR
4254). All SIPs and SIP revisions that are developed after that date
must use the new model to estimate motor vehicle emissions. The release
of MOBILE6 also began a 24-month grace period for conformity. All
conformity determinations that are initiated after January 29, 2004
must use MOBILE6. As discussed in the following section of this notice,
MOBILE6 has now been revised with the release of MOBILE6.2. Besides the
release of updated emissions models, another circumstance that has
changed since adoption of the 2000 CO plan is the change in the
expected rate of population growth in Las Vegas Valley. The most recent
forecasts show population growth outpacing the corresponding
projections used for the 2000 CO plan.
In response to these changes, DAQEM, in consultation with the
Regional Transportation Commission of Southern Nevada (RTC), undertook
a comprehensive air quality planning effort to review and update the
2000 CO plan and the associated motor vehicle emission budgets to
maintain consistency for future conformity findings. The planning
efforts included detailed technical analyses, such as preparation of
new base and future year emissions inventories and regional and hotspot
dispersion modeling, and culminated in the preparation, adoption and
submittal of the 2005 CO plan, which is the subject of today's proposed
action.

E. What Are MOBILE6 and MOBILE6.2?

MOBILE is an EPA emissions factor model for estimating pollution
from on-road motor vehicles in states except for California. MOBILE
calculates emissions of volatile organic compounds (VOCs), nitrogen
oxides (NO_X) and carbon monoxide (CO) from passenger cars,
motorcycles, buses, and light-duty and heavy-duty trucks. The model
accounts for the emission impacts of factors such as changes in vehicle
emission standards, changes in vehicle populations and activity, and
variation in local conditions such as temperature, humidity, fuel
quality, and air quality programs.
MOBILE is used to calculate current and future inventories of motor
vehicle emissions at the national and local level. These inventories
are used to make decisions about air pollution policies and programs at
the federal, state and local level. Inventories based on MOBILE are
also used to meet the Federal Clean Air Act's SIP and transportation
conformity requirements.
The MOBILE model was first developed in 1978. It has been updated
many times to reflect changes in the vehicle fleet and fuels, to
incorporate EPA's growing understanding of vehicle emissions, and to
cover new emissions regulations and modeling needs. Although some minor
updates were made in 1996 with the release of MOBILE5b, MOBILE6 was the
first major revision to MOBILE since MOBILE5a was released in 1993.
Released in 2002 (67 FR 4254, January 29, 2002), MOBILE6 incorporates
new and improved vehicle and emissions data and a new understanding of
vehicle emissions processes.
In 2004 (69 FR 28830), MOBILE6 was updated with the release of
MOBILE6.2, which adds the capability to generate direct particulate
matter emission factors and emission factors for particulate
precursors. MOBILE6.2 also corrects some minor coding errors in MOBILE6
and incorporates some revisions to CO emission factors for cars and
light-duty trucks that meet national low emission vehicle (NLEV), low
emission vehicle (LEV), and Tier 2 vehicle standards. MOBILE6.2 is now
the latest emission model released by EPA and should be used by all
areas for SIP and conformity analyses. Further details on MOBILE models
can be found at http://www.epa.gov/otaq/mobile6.htm.

F. What Is the Current Status of CO Levels in Las Vegas Valley and How
Do the Levels Compare With the Federal Standards?

The national 8-hour CO ambient standard is attained when the
highest 8-hour CO concentration of 9 parts per million (ppm) is
exceeded no more than one time in a calendar year. Since the initial
operation of CO monitors in Las Vegas Valley in the 1970's, exceedances
of the CO standard occurred relatively frequently during the winter
months, but, with the implementation of various State and local CO
control measures (e.g., fuel specifications and vehicle I/M program)
and also the implementation of the Federal motor vehicle control
program (e.g., exhaust emission standards for new light-duty vehicles,
light-duty trucks, and heavy-duty trucks), CO levels trended downward
in Las Vegas Valley despite large increases in population and VMT
through the 1980's and 1990's.
By the late-1990's, ambient CO conditions had improved to such an
extent that exceedances were no longer recorded at any of the CO
monitoring stations. The last exceedances of the 8-hour CO standard in
Las Vegas Valley were recorded in 1998, and based on the record of
clean data during the 1999-2000 period, we determined that Las Vegas
Valley attained the CO NAAQS by the applicable ``serious'' area
attainment date of December 31, 2000. See 70 FR 31353 (June 1, 2005).
Since 2000, and through year 2005, the highest 8-hour CO concentration
measured by the CO monitoring network in Las Vegas Valley was 7 ppm
(measured at the Sunrise Acres monitoring site), which is well below
the CO standard of 9 ppm. Thus, after attaining the CO standard in
2000, Las Vegas Valley has continued to attain the standard up to the
present time.

III. Review of Las Vegas Valley 2005 CO Plan Submittal

A. What Is the Purpose and Content of Nevada's Submittal?

DAQEM's purpose in preparing the 2005 CO plan is to update the CO
motor vehicle emissions budgets from the 2000 CO plan for use in
transportation conformity determinations.
The 2005 CO plan generally follows the outline of the 2000 CO plan
and provides expanded discussion of the plan elements for which new
information is available or for which circumstances have changed since
adoption of the previous plan. First, the 2005 CO plan discusses the
changes to the CO monitoring network and ambient CO level trends since
2000, as well as

[[Page 26913]]

the results of the CO saturation study, which was completed in January
2002. See chapter 2 and appendix B of the 2005 CO plan. The 2005 CO
plan then provides a comprehensive revision to the base year (1996)
emissions inventory and future year emissions projections reflecting
updated underlying data, such as population and VMT forecasts, and also
updated methods, such as MOBILE6.2 and NONROAD2004 for on-road and
nonroad sources, respectively. The 2005 CO plan summarizes the control
measures that have contributed to attainment of the CO NAAQS in Las
Vegas Valley and that are being counted on for continued attainment of
the standard but neither repeals nor modifies any such measure. The
remainder of the 2005 CO plan provides updated dispersion modeling
results reflecting the updated emissions estimates and extends the
showing of continued attainment from 2020 (as provided for in the 2000
CO plan) to 2030, and supporting the establishment of new motor vehicle
emissions budgets.
Included with the 2005 CO plan are technical appendices which
include a technical support document for the emission inventory and
dispersion modeling, the carbon monoxide monitoring saturation study, a
study on the effectiveness of the area's vehicle I/M program, airport
modeling studies, a support letter from the area's Metropolitan
Planning Organization (i.e., the RTC) and documentation of the public
review process for the plan.
Enclosed with the 2005 CO plan, NDEP also submitted a report
entitled, ``Supplement to the Carbon Monoxide State Implementation Plan
Revision,'' which was prepared by DAQEM in response to comments raised
by EPA after adoption of the 2005 CO plan on October 4, 2005. The
supplemental report presents an air quality trends analysis in further
support for the plan's forecast of continued attainment through 2030
with the plan's proposed motor vehicle emissions budgets.

B. How Is EPA Evaluating This Submittal?

Section 110(l) of the Clean Air Act requires SIP revisions to be
subject to reasonable notice and public hearing prior to adoption by
the applicable State or local agency and submittal to EPA. In this
instance, the Clark County Board of Commissioners adopted the 2005 CO
plan on October 4, 2005, following a 30-day comment period and a public
hearing, properly noticed in a newspaper of general circulation in Las
Vegas Valley. NDEP, the Governor's designee for SIP submittals in
Nevada, then submitted the 2005 CO plan to EPA as a revision to the
Nevada SIP on February 14, 2006. Thus, we find that the procedural
requirements for SIP submittals under CAA section 110(l) have been
satisfied.
Section 110(l) also prohibits EPA from approving any SIP revision
that would interfere with any applicable requirement concerning
attainment and reasonable further progress or any other applicable
requirement of the Act. In this instance, the SIP revision involves an
update to emissions inventories, dispersion modeling, and motor vehicle
emissions budgets previously approved by EPA.
We review emissions inventories to ensure they are comprehensive
and accurate and are based on the latest planning assumptions and
emissions models. We review modeling demonstrations to ensure they are
consistent with the underlying emissions estimates and reflect
reasonable methods and assumptions. We review motor vehicle emissions
budgets to ensure that the budgets are clearly related to the emissions
inventory and the control measures in the applicable plan and that the
budgets, when considered together with all other emissions sources, are
consistent with applicable requirements for reasonable further
progress, attainment, or maintenance.
As described in the following sections of this notice, we conclude
that, for the base year (1996) through 2020, the models and methods
used to revise the emissions inventories and dispersion modeling are
acceptable and that the motor vehicle emissions budgets are clearly
related to the revised inventories and EPA-approved CO control measures
for Las Vegas Valley and that the budgets are consistent with continued
attainment of the CO NAAQS in Las Vegas Valley through 2030 and thus
approvable under CAA section 110(l). However, the 2005 CO plan fails to
demonstrate continued attainment in the horizon year of 2030 because
the micro-scale modeling for Clark County airports extends only through
2020. Based on these conclusions, we are proposing to approve the Las
Vegas Valley 2005 CO plan and related motor vehicle emissions budgets
as a revision to the Nevada SIP on the condition that Clark County and
the State of Nevada withdraw the 2030 motor vehicle emissions budgets,
or to disapprove the plan in the alternative if no such withdrawal is made.

C. How Have Emissions of Carbon Monoxide in Las Vegas Valley Changed?

The emissions inventory is a list, by source, of the air
contaminants directly emitted into the air within a given area. The
data in the emissions inventory are based on calculations and are
developed using emission factors, which convert source activity levels
into an estimate of emissions contributions for those sources. For the
2000 CO plan, the Clark County Department of Air Quality, which
performed the air quality planning functions now performed by DAQEM,
developed a base case emissions inventory for the base year 1996 and
then projected inventories for years 2000, 2010 and 2020. The general
categories of CO sources included on-road motor vehicles, nonroad
mobile sources, and stationary area and point sources, and the
emissions estimates corresponded to an average day during the peak CO
(i.e., winter) season.\4\
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\4\ That is, except for on-road motor vehicles, which reflect
average daily conditions during the month of December.
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For the 2005 CO plan, DAQEM developed updated estimates for the
1996 base year and for years 2010 and 2020 but also developed new
estimates of emissions for certain interim years, 2006 and 2015, not
previously quantified, and developed an emissions inventory for a new
horizon year, 2030. The 2005 CO plan inventories cover the same basic
source categories but adjust the emissions estimates to correspond to
the second Sunday and second Monday in December consistent with the
December 8-9, 1996 episode used for dispersion modeling purposes in the
plan. The most significant changes in the emission inventories for the
2005 CO plan are in the on-road motor vehicle and nonroad mobile source
categories.
The 2005 CO plan is based on the latest available forecasts of
population. These updated forecasts reflect a higher rate of growth in
population in Las Vegas Valley than had been assumed for the 2000 CO
plan. For example, for years 2010 and 2020, the population forecasts
used in the 2005 CO plan are 25 to 30% higher than the corresponding
forecasts used in the 2000 CO plan.
The RTC used the updated population forecasts to provide updated
travel demand forecasts for the purposes of emissions inventory
preparation and dispersion modeling for the 2005 CO plan. To develop
the travel demand forecasts for future years, RTC used the TransCAD
travel demand model, a model that has replaced TRANPLAN, the older
model that had been used for the 2000 CO plan. For the base year, the
original TRANPLAN-derived data was used, but TransCAD-derived data was
used for all future years. TransCAD

[[Page 26914]]

incorporates a number of refinements as compared to TRANPLAN including
more accurate temporal and spatial allocation of vehicle miles traveled
(VMT). Further details regarding VMT processing are provided in chapter
2 of DAQEM's Technical Support Document, which is included as appendix
A of the 2005 CO plan.
RTC's updated travel demand forecasts provided the basis for
updated motor vehicle emissions estimates through application of
MOBILE6.2 emissions factors. As noted above, MOBILE6.2 represents a
significant revision of the previous model, MOBILE5b, which was used
for the 2000 CO plan, is the latest EPA emissions factor model for
estimating pollution from on-road motor vehicles, and incorporates the
effects of national vehicle control programs and, with the appropriate
input controls, the effects of local control programs such as the
State's alternate ``low'' enhanced vehicle I/M program and the
wintertime gasoline specifications for RVP, sulfur and oxygen.
The MOBILE6.2-derived emissions factors for the 2005 CO plan
reflect an assumed vehicle I/M effectiveness of 100% instead of 50% as
assumed for the 2000 CO plan. To provide support for this change, DAQEM
commissioned a study of the effectiveness of the decentralized (i.e.,
privately owned and operated as opposed to state-run or
``centralized'') network of I/M testing stations in Las Vegas Valley
that concluded that the ``test-and-repair'' stations are equally as
effective as ``test-only'' stations at reducing emissions. We note that
Nevada I/M regulations allow ``test-only \5\'' stations to perform
certain types of automotive services (e.g., change of oil; and
replacement of oil, air, or fuel filters) that ``test-only'' stations
as defined in EPA's I/M regulations are not allowed to perform. See 40
CFR 51.353(a).
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\5\ Vehicles are tested annually in a decentralized network that
employs stations licensed as either test-only or test-and-repair.
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However, we also note that, based on information contained in the
DAQEM study cited above, only 25% of the ``test-only'' stations in Las
Vegas Valley actually offer these limited services and 75% only perform
emissions testing. Thus, the presumptive equivalency (to centralized
test-only stations), i.e., assumption of 100% I/M effectiveness,
allowed under 40 CFR 51.353(a) is not unreasonable with respect to the
``test-only'' stations in Las Vegas Valley. Furthermore, given the
results of the DAQEM study cited above that the ``test-and-repair''
stations are equally as effective as the ``test-only'' stations, the
assumption of 100% effectiveness for the overall I/M program in Las
Vegas Valley is also not unreasonable. DAQEM included a copy of the
study of I/M effectiveness as appendix C of the 2005 CO plan.
With respect to nonroad mobile sources, the 2005 CO plan
incorporates updated information concerning airport and railroad
operations and activities, and reflects use of an emissions model
(NONROAD) \6\ for the other types of nonroad sources. NONROAD was not
available at the time when the 2000 CO plan was being prepared and
represents a significant refinement in the method for estimating
emissions from nonroad sources as compared to the 1991 EPA study that
was used for the 2000 CO plan. Clark County land use/land cover data
were used as inputs to the NONROAD model to estimate revised emissions
for these categories in both the base and future year inventories.
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\6\ NONROAD is EPA's model for estimating emissions from nonroad
vehicles such as construction equipment, lawn and garden equipment
and recreational equipment. For the 2005 CO plan, DAQEM used the
latest version of NONROAD (NONROAD2004) available at the time of
plan preparation. NONROAD2004 has since been superseded by
NONROAD2005, which is the final version of NONROAD. The previous
versions, including NONROAD2004, were draft versions, but
nonetheless represented the best method for calculating emissions
from nonroad mobile sources, excluding commercial marine,
locomotive, and aircraft, at the time of their release.
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For the 2005 CO plan, stationary area and point sources are largely
consistent with the corresponding emissions estimates for these source
categories in the 2000 CO plan except for seven specific point sources
for which the future-year projections in the 2005 CO plan incorporate
potentials to emit (rather than projected actual emissions) plus a 70
tons per year additional buffer.
Tables 1 and 2 summarize the emissions estimates contained in the
2005 CO plan. Table 1 represents the second Sunday in December and
table 2 represents the second Monday in December. The inventories were
prepared for these particular conditions because the dispersion
modeling demonstration of continued attainment is predicated on the
December 8-9, 1996 episode.
As shown in these two tables, on-road motor vehicles continue to
represent the most significant source category for CO emissions in Las
Vegas Valley, but the contribution from on-road sources is expected to
decrease from roughly 70 to 75% of the total CO inventory under
existing conditions to 65 to 70% by 2030. Nonroad mobile source account
for 20 to 25% of the total inventory under existing conditions but the
relative contribution from this source category is expected to increase
to 25 to 30% by 2030. The 2005 CO plan estimates that stationary area
and point sources account for 5 to 10% of the CO inventory both now and
in the future.

Table 1.--Las Vegas Valley CO Nonattainment Area Emissions, December Sunday (Tons) by Source Category
----------------------------------------------------------------------------------------------------------------
Source category 1996 2006 2010 2015 2020 2030
----------------------------------------------------------------------------------------------------------------
On-road motor vehicle......................... 329 275 287 276 273 296
Nonroad mobile................................ 102 89 99 109 121 143
Stationary area............................... 9 13 14 16 18 22
Point......................................... 3 16 16 16 16 16
-----------------------------------------------------------------
Total..................................... 445 392 415 418 428 477
----------------------------------------------------------------------------------------------------------------

Table 2.--Las Vegas Valley CO Nonattainment Area Emissions, December Monday (Tons) by Source Category
----------------------------------------------------------------------------------------------------------------
Source category 1996 2006 2010 2015 2020 2030
----------------------------------------------------------------------------------------------------------------
On-road motor vehicle......................... 511 441 464 451 447 486
Nonroad mobile................................ 138 111 123 136 150 178

[[Page 26915]]

Stationary area............................... 10 13 15 17 19 23
Point......................................... 3 16 16 16 16 16
-----------------------------------------------------------------
Total..................................... 662 581 617 619 631 702
----------------------------------------------------------------------------------------------------------------
Source: Derived from 2005 CO plan, Table 3-12.

Based on our review of the documentation provided in the 2005 CO
plan as summarized above, we find that the revised base year and future
year CO emissions inventories reflect the latest planning assumptions
and emissions models and provide a comprehensive and accurate
assessment of CO emissions in Las Vegas Valley for the various impact
analysis years. Furthermore, we find that the revised inventories
provide a reasonable basis upon which to update the dispersion modeling
analysis, as discussed in the following section of this notice.

D. How Has the Attainment Demonstration Changed?

The 2000 CO plan's attainment demonstration included both an
areawide and a hot-spot modeling analysis at heavily-traveled
intersections, and the revised demonstration in the 2005 CO plan also
includes both the regional and micro-scale modeling analyses. As in the
previous attainment demonstration, areawide analysis was conducted
using the Urban Airshed Model (UAM), according to our ``Guidance for
Application of Urban Areawide Models for CO Attainment Demonstrations''
(1992).
The 2000 CO plan provided a modeling demonstration of attainment
from the nonattainment conditions in 1996 for the applicable attainment
date of 2000 through implementation of new control measures. The 2000
CO plan also demonstrated continued attainment beyond 2000 by
developing CO level estimates for impact analysis years 2010 and 2020.
Since Las Vegas Valley has already attained the CO NAAQS, the 2005 CO
plan does not need to demonstrate attainment per se but must
demonstrate continued attainment of the standard, and it does so for
the following impact analysis years: 2006, 2010, 2015, 2020 and 2030.
For the 2005 CO plan, the UAM analysis uses the same December 8-9,
1996 episode as in the previous demonstration, but with the revised
emission inventory information described in the previous section of
this notice. Overall, the spatial pattern of predicted 8-hour maximum
CO agrees with the previous modeling in the 2000 CO plan and with the
distribution of observed CO for this period. Unlike the modeling
documented in the 2000 CO plan, no external scaling was needed for the
UAM results in the new modeling runs. The maximum CO concentration
predicted for the base case 1996 episode was 11.4 ppm which is close to
the 11.2 ppm predicted in the 2000 CO plan, along Las Vegas Boulevard
near the intersection with Spring Mountain Road. Model performance for
the base year UAM simulation is within our acceptable range of
accuracy: +19 percent for the unpaired peak prediction, -15% percent
for the paired peak prediction, and 1 hour for the timing error. See
the 2005 CO plan, page 5-2. Once the model performance was verified,
the 1996 base case emission inventory was projected into the future and
then these projected emission inventories were used with the 1996
meteorological conditions to simulate the impact of emission changes in
the future.
The simulations showed that emissions in future years with controls
would continue to support peak concentrations well below the 9 ppm 8-
hour CO standard. Concentrations for the 8-hour average are shown for
the maximum concentration predicted over the modeling domain. The
predicted regional maximum 8-hour average CO concentration is 8.0 ppm
in the year 2030, assuming continued implementation of all previously
adopted control measures (e.g., the vehicle I/M program and the
wintertime gasoline specifications). Results for all future years
modeled are shown in table 3.

Table 3.--UAM Results for Future Year Scenarios
------------------------------------------------------------------------
Concentrations
Year (ppm)
------------------------------------------------------------------------
2006................................................. 7.37
2010................................................. 7.17
2015................................................. 6.47
2020................................................. 6.74
2030................................................. 7.96
------------------------------------------------------------------------
Source: 2005 CO plan, Table 6-3.

The UAM analysis thus shows attainment with a margin of safety
based on continued implementation of fully adopted control measures.
However, an additional model, CAL3QHC must be used to determine the
maximum CO levels in the area. CAL3QHC is needed to predict the micro-
scale impacts of vehicles operating at congested intersections.
Vehicles operating within congested conditions spend more time in idle
modes that can contribute to high levels of CO near the roadways. As in
the 2000 CO plan, micro-scale modeling was completed for three
intersections (1) Charleston Blvd./Eastern Avenue, (2) Charleston
Blvd./Fremont Street and (3) Eastern Avenue/Fremont Street. These three
intersections comprise the ``5 points'' area, which is near the Sunrise
Acres CO monitoring station. For years 2006, 2010, 2015, 2020 and 2030,
traffic data from the roadways were combined with emission factors from
MOBILE6.2 and meteorological data to predict local hotspot
concentrations. These hourly results from the micro-scale model were
then combined with hourly concentrations from the background UAM grid
cell to compute maximum running 8-hour concentrations. The combined
results of the CAL3QHC and UAM results are shown in Table 4 below.

[[Page 26916]]

Table 4.--Intersection Maximum Predicted Combined 8-Hour CO Levels
[ppm]
----------------------------------------------------------------------------------------------------------------
Intersection 2006 2010 2015 2020 2030
----------------------------------------------------------------------------------------------------------------
Charleston/Eastern....................................... 6.14 5.61 4.97 4.67 4.83
Charleston/Fremont....................................... 5.09 4.81 4.31 4.07 4.20
Eastern/Fremont.......................................... 5.66 5.32 4.76 4.48 4.58
----------------------------------------------------------------------------------------------------------------
Source: 2005 CO plan, Table 6-5.

As in the 2000 CO plan, in addition to roadway intersections
modeling, the 2005 CO plan includes an analysis of CO levels at
airports in Las Vegas Valley. To model the impact of airport sources,
the Emissions and Dispersion Modeling System (EDMS) model was again
used. This model was developed for evaluating the specific emission
sources typically located at airports. The hotspot results from EDMS
must be combined with the results of the UAM analysis to predict the
concentrations at receptors around the airports. The 2005 CO plan
presents the results of the combined UAM and EDMS models for the all
future years in table 4-5 of appendix A. No values were modeled above
the 9.0 ppm CO standard at any publicly accessible receptor location.
The peak combined concentration at McCarran International Airport for
future years is 8.45 ppm for 2020. We note however that the micro-scale
analysis for the airports' environs does not extend beyond year 2020,
and thus that analysis demonstrates continued attainment through 2020,
but not in year 2030.
Based on our review of the documentation provided in the 2005 CO
plan as summarized above, we find that the revised modeling results are
consistent with the underlying emission estimates and reflect
reasonable methods and assumptions. Further, we find that the revised
modeling results demonstrate continued attainment of the CO NAAQS in
Las Vegas Valley through 2020 but that the plan fails to demonstrate
continued attainment in 2030 because of the lack of micro-scale
analysis in the environs of the Clark County airports in that year.

E. Are Las Vegas Valley's Motor Vehicle Emissions Budgets Approvable?

The CO motor vehicle emissions budgets from the EPA-approved 2000
CO plan are 310.2, 329.5, and 457.4 tons of CO per average (December)
day for years 2000, 2010, and 2020, respectively. Conformity
determinations must be made using the latest planning assumptions and
emissions models. In light of updated population forecasts for Las
Vegas Valley that show higher levels of growth than expected in the
2000 CO plan as well as the significant differences between the
MOBILE6.2 and MOBILE5b emissions model, DAQEM, in consultation with the
RTC, developed the 2005 CO plan to replace the budgets from the 2000 CO
plan, which are based on outdated population forecasts and MOBILE5b,
with new budgets reflecting the latest planning assumptions and
MOBILE6.2 and thereby provide for consistency between the CO attainment
planning in Las Vegas Valley and future conformity determinations.
During the course of preparing the 2005 CO plan, DAQEM recognized,
from the revised dispersion modeling analysis discussed above, the
possibility that the reduction in CO emissions factors over time due to
the implementation of new Federal motor vehicle standards, the area's
I/M program and wintertime gasoline specifications, would offset the
higher level of expected population growth and keep the area in
attainment of the CO NAAQS with some margin of safety. Therefore, as
part of this SIP revision, DAQEM explored scaling up emissions to
determine how much more the area's emissions estimate could grow while
still keeping the area in attainment.
DAQEM conducted several sensitivity analyses to determine the
impacts of scaling up emissions in the modeling domain. In the first
test runs, the modeling domain was split into a central urban core and
an outer domain. Total emissions for all sources were doubled in the
outer domain. The resulting UAM predicted concentrations for all future
years modeled are shown in table 5. A comparison of the results in
table 5 with the results in table 3 shows that CO concentrations only
increase slightly with the doubling of outer domain CO emissions.

Table 5.--UAM Results for Future Year Scenarios With Doubled Outer
Domain Emissions
------------------------------------------------------------------------
Concentrations
Year (ppm)
------------------------------------------------------------------------
2006................................................. 7.41
2010................................................. 7.24
2015................................................. 6.54
2020................................................. 6.80
2030................................................. 8.03
------------------------------------------------------------------------
Source: 2005 CO plan, Table 6-3.

In the next sensitivity analysis, on-road motor vehicle emissions
were scaled up from the base case over the entire modeling domain until
the modeled UAM concentrations reached 8.9 ppm. Then, motor vehicle
emissions in the outer domain were increased an additional 70%. The
final revised emissions for this sensitivity analysis are shown in
table 6.\7\
---------------------------------------------------------------------------

\7\ Note that DAQEM has not submitted, and EPA is not acting on,
sub-area motor vehicle emission budgets for the Las Vegas area. The
modeling domain was split into urban and outer areas so that DAQEM
could examine the sensitivity of the model to increases in emissions
in the outer areas. For transportation conformity purposes, we are
only acting on the total motor vehicle emissions budgets from both
areas combined together.

Table 6.--Base and Scaled On-Road Emissions For the Final Sensitivity Analysis
[Tons per December weekday]
----------------------------------------------------------------------------------------------------------------
Base Scaled
Year -----------------------------------------------------------------
Urban Outer Total Urban Outer Total
----------------------------------------------------------------------------------------------------------------
2006.......................................... 345 96 441 427 196 623
2010.......................................... 347 117 464 438 252 690
2015.......................................... 320 131 451 453 315 768

[[Page 26917]]

2020.......................................... 309 138 447 463 354 817
2030.......................................... 318 167 485 464 417 881
----------------------------------------------------------------------------------------------------------------
Source: Derived from 2005 CO plan, Table 6-4.

The final scaled revised emissions were then input into UAM to
determine the resulting peak UAM concentrations. Then, to assess the
micro-scale impacts of increased numbers of vehicles operating at
congested intersections, the UAM results in the appropriate grid cells
were combined with additional CAL3QHC modeling of increased traffic.
Those combined results, and the maximum modeled UAM CO concentrations
are presented in table 7.
Increased UAM concentrations in grid cells around the airports were
also examined with the combined EDMS modeling. Again, no values were
modeled above the 9.0 ppm standard in any publicly accessible receptor
locations. The peak combined concentration at McCarran International
Airport for future years is 8.98 ppm for 2020. However, as noted in the
previous section of this notice, the micro-scale analysis for the
airports' environs does not extend beyond 2020.

Table 7.--UAM and CAL3QHC Maximum Predicted 8-hour CO Levels
[ppm]
----------------------------------------------------------------------------------------------------------------
Modeled cell or intersection 2006 2010 2015 2020 2030
----------------------------------------------------------------------------------------------------------------
Peak UAM Grid Cell (Domain-wide):........................ 8.96 8.98 8.98 8.97 8.97
Peak Combined UAM (for applicable grid cell) & CAL3QHC:
Charleston/Eastern....................................... 7.45 6.97 6.85 6.78 6.84
Charleston/Fremont....................................... 6.17 5.99 5.93 5.88 5.91
Eastern/Fremont.......................................... 6.85 6.61 6.54 6.48 6.45
----------------------------------------------------------------------------------------------------------------
Source: 2005 CO plan, Appendix A: Tables 5-5 and Table 5-6.

Since the maximum modeled concentrations for this final sensitivity
test resulted in concentrations close to the standard, to account for
modeling uncertainty, DAQEM also completed an air quality trend
analysis for the ten year period from 1996 to 2005 to provide
additional support for the modeling demonstration. DAQEM prepared this
additional analysis in response to EPA comments after adoption of the
2005 CO plan by the Clark County Board of Commissioners, and NDEP
enclosed this analysis, entitled ``Supplement to the Carbon Monoxide
State Implementation Plan Revision,'' with the February 14, 2006 SIP
revision containing the 2005 CO plan.
DAQEM conducted the trend analysis based on meteorological and
monitoring data collected at the Sunrise monitoring station for each
day from November 1st though January 31st (CO season), because the 8-
hour maximum CO concentrations are typically recorded at this site.
After normalization, linear regression analysis and a multivariate
linear regression analysis was performed to predict trends at the site.
The results of the analysis show a continued downward trend of maximum
CO concentrations for future years, independent of meteorology, and
suggest that event if CO emissions were increased by 80%, that future
emissions would still be below 9.0 ppm, i.e., in attainment with the CO
NAAQS.
The 2005 CO plan establishes the emissions shown in the final
scaled on-road motor vehicle emissions table (see the far-right column
in table 6, above) as the new motor vehicle emissions budgets for Las
Vegas Valley. The budgets are also summarized below in table 8. These
budgets reflect allocations of the safety margin to the motor vehicle
source category varying from approximately 180 tons per year in 2006 to
nearly 400 tons per day in 2030. Based on the scaled modeling results
in the 2005 CO plan and the supplemental trend analysis prepared by
DAQEM, we find that, with the exception of the 2030 budget, replacement
of the current budgets with the motor vehicle emissions budgets in the
2005 CO plan would not interfere with continued attainment of the CO
NAAQS in Las Vegas Valley and are therefore approvable. However, we
cannot find that establishment of the 2030 budget would not interfere
with continued attainment because the micro-scale analysis in the
environs of the County airports does not extend to that year.

Table 8.--On-Road Motor Vehicle Emissions Budgets
[Tons per December weekday]
------------------------------------------------------------------------
Year Budget
------------------------------------------------------------------------
2006......................................................... 623
2010......................................................... 690
2015......................................................... 768
2020......................................................... 817
2030......................................................... 881
------------------------------------------------------------------------
Source: 2005 CO plan, Table 7-1.

F. How Does This Action Affect Transportation Conformity?

Under section 176(c) of the Act, transportation plans, programs,
and projects in nonattainment or maintenance areas that are funded or
approved under 23 U.S.C or Federal Transit Laws, must conform to the
applicable SIPs. In short, a transportation plan is deemed to conform
to the applicable SIP if the emissions resulting from implementation of
that transportation plan are less than or equal to the motor vehicle
emissions budget established in the SIP for the attainment year and
other analysis years. If the condition is met on our proposed approval
(i.e., Clark County and the State of Nevada withdraw the 2030 budget)
and our action is otherwise finalized as

[[Page 26918]]

proposed here today, the CO motor vehicle emissions budgets shown in
table 8 above (minus the 2030 budget) must be used by U.S. Department
of Transportation and the Regional Transportation Commission of
Southern Nevada for transportation conformity determinations made after
the effective date of our final rule.

IV. Proposed Action and Request for Public Comment

Pursuant to section 110(k) of the Act, we propose to approve the
Carbon Monoxide State Implementation Plan Revision, Las Vegas Valley
Nonattainment Area, Clark County, Nevada (October 2005), which was
adopted by the Clark County Board of Commissioners on October 4, 2005
and submitted to EPA by NDEP on February 14, 2006, as a revision to the
Nevada SIP on the condition that Clark County and the State of Nevada
withdraw the 2030 motor vehicle emission budget, or, in the
alternative, we propose to disapprove the plan. The plan disapproval
will not trigger any Clean Air Act 179(b) sanctions.
Our proposed approval is based on our evaluation of the plan
submittal and determination that the plan's revised base year and
projected emission inventories and modeling demonstration of continued
attainment of the CO standard through 2020 reflect acceptable methods
and the most recent models and planning assumptions. Our proposed
disapproval is based on our finding that the plan does not demonstrate
continued attainment in year 2030 because it lacks micro-scale modeling
analysis for the environs of the County's airports in that year.
Furthermore, we find that, with the exception of the 2030 budget,
the new motor vehicle emissions budgets established in the plan and
reflecting scaled inventories are also consistent with continued
attainment of the CO NAAQS in Las Vegas Valley. Thus, we propose to
approve the following motor vehicle emissions budgets from the 2005 CO
plan as meeting the purposes of section 176(c)(1) and the
transportation conformity rule at 40 CFR part 93, subpart A contingent
upon the withdrawal of the 2030 budget by Clark County and the State of
Nevada, and to disapprove the submitted budgets in the 2005 CO plan, in
the alternative, if no such withdrawal is made:

CO Motor Vehicle Emissions Budget
[December weekday]
------------------------------------------------------------------------
Tons per
Year day
------------------------------------------------------------------------
2006......................................................... 623
2010......................................................... 690
2015......................................................... 768
2020......................................................... 817
------------------------------------------------------------------------

Our action in approving the submitted plan revision and related
motor vehicle emissions budgets, if the county and state withdraw the
2030 budget and if this action is otherwise finalized as proposed,
would have the effect of replacing the existing CO motor vehicle
emissions budgets from the Las Vegas Valley 2000 CO plan for the
purposes of transportation conformity. EPA is soliciting public comment
on the issues discussed in this document. These comments will be
considered before taking final action.

V. Statutory and Executive Order Reviews

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 13211, ``Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use'' (66 FR 28355,
May 22, 2001). This proposed action merely approves an air
quality plan as meeting Federal requirements or disapproves the plan in
the alternative 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 proposed rule approves or
disapproves in the alternative 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 (Pub. L. 104-4).
This proposed rule also does not have tribal implications because
it will 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 (59 FR 22951, November 9, 2000). This proposed action also
does not have Federalism implications because it does not 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). This
proposed action merely approves a state plan implementing a Federal
standard or disapproves the plan in the alternative, 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, ``Protection of Children from
Environmental Health Risks and Safety Risks'' (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. 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, Carbon monoxide,
Intergovernmental relations, Reporting and recordkeeping requirements.

Dated: May 1, 2006.
Wayne Nastri,
Regional Administrator, Region IX.
[FR Doc. E6-7032 Filed 5-8-06; 8:45 am]
BILLING CODE 6560-50-P

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