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Clean Air Act Reclassification; Nevada-Clark County Nonattainment Area; Carbon Monoxide
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
[Federal Register: August 12, 1996 (Volume 61, Number 156)] [Proposed Rules] [Page 41759-41764] From the Federal Register Online via GPO Access [wais.access.gpo.gov]
ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 81 [NV-029-0001; FRL-5549-5] Clean Air Act Reclassification; Nevada-Clark County Nonattainment Area; Carbon Monoxide AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule.
SUMMARY: EPA proposes to find that the Clark County, Nevada carbon monoxide (CO) nonattainment area has met the criteria in section 186(b)(4) of the Clean Air Act (CAA): it exceeded the CO National Ambient Air Quality Standard (NAAQS) once in 1995; it has adopted and implemented the CAA required moderate nonattainment area control measures; and, it has demonstrated progress towards attaining the CO NAAQS. As a result of this finding, EPA proposes to grant a one-year extension of Clark County's moderate area attainment date from December 31, 1995 to December 31, 1996. EPA's proposed finding is based on a review of monitored air quality data for compliance with the CO NAAQS, as well as the air quality planning progress of Clark County. If EPA takes final action on this proposed finding, the Clark County CO nonattainment area will remain classified as a moderate CO nonattainment area as a result of extending the CAA mandated attainment date for one year. The intended effect of extending the attainment date is to allow Nevada and Clark County either to fully implement and strengthen current CO control measures, or to adopt additional control measures prior to the 1996-97 winter CO season in an effort to attain the CO NAAQS. DATES: Written comments on this proposal must be received by September 11, 1996. ADDRESSES: Written comments should be sent to: Wallace Woo, Chief, Plans Development Section, A-2-2, U.S. Environmental Protection Agency, Region 9, 75 Hawthorne Street, San Francisco, California 94105.
The rulemaking docket for this proposal, Docket No. 96-NV-PL-001, may be inspected and copied at the following location between 8 a.m. and 4:30 p.m. on weekdays. A reasonable fee may be charged for copying parts of the docket.
U.S. Environmental Protection Agency, Region 9, Air and Toxics Division, Plans Development Section, A-2-2, 75 Hawthorne Street, San Francisco, California 94105.
Copies of the docket are also available at the State and local offices listed below:
Nevada Division of Environmental Protection, 333 West Nye Lane, Carson City, Nevada, 89710; and,
Clark County Department of Comprehensive Planning, 500 South Grand Central Parkway, Suite 3012, Las Vegas, Nevada, 89155-1741. FOR FURTHER INFORMATION CONTACT: Jerry Wamsley, A-2-2, Air and Toxics Division, U.S. Environmental Protection Agency, Region 9, 75 Hawthorne Street, San Francisco, California 94105, (415) 744-1226. SUPPLEMENTARY INFORMATION: I. Background A. CAA Requirements and EPA Actions Concerning Designation and Classifications With enactment of the Clean Air Act Amendments of 1990, under section 107(d)(1)(C) of the Clean Air Act (CAA), each carbon monoxide (CO) area designated nonattainment prior to enactment of the 1990 Amendments was designated nonattainment by operation of law. Under section 186(a) of the CAA, each CO area designated nonattainment under section 107(d) was also classified by operation of law as either ``moderate'' or ``serious'' depending on the severity of the area's air quality problem. CO areas with design values between 9.1 and 16.4 parts per million (ppm) were classified as moderate. States containing areas that were classified as moderate nonattainment by [[Page 41760]] operation of law under section 107(d) were required to submit State implementation plans (SIPs) designed to attain the CO national ambient air quality standard (NAAQS) as expeditiously as practicable but no later than December 31, 1995.
On November 6, 1991, Clark County was designated nonattainment for CO and was classified as a ``high'' moderate area given its design value of 14.4 ppm (See 56 FR 56694). Clark County's nonattainment designation and classification is codified at 40 CFR part 81.329. The moderate area SIP requirements are set forth in section 187(a) of the CAA and differ depending on whether the area's design value is below or above 12.7 parts per million (ppm). With its design value of 14.4 ppm, Clark County is required to meet the ``high'' moderate nonattainment area requirements and attain the CO NAAQS by December 31, 1995. B. Reclassification to a Serious Nonattainment Area EPA has the responsibility, pursuant to sections 179(c) and 186(b)(2) of the CAA, of determining within six months of the applicable attainment date, December 31, 1995, whether a moderate area has attained the CO NAAQS. Under section 186(b)(2)(A), if EPA finds that a moderate area has not attained the CO NAAQS, it is reclassified as serious by operation of law. Pursuant to section 186(b)(2)(B) of the Act, EPA must publish a notice in the Federal Register identifying areas which failed to attain the standard and therefore must be reclassified as serious by operation of law. EPA makes attainment determinations for CO nonattainment areas based upon whether an area has two years (or eight consecutive quarters) of clean air quality data.<SUP>1 Section 179(c)(1) of the Act states that the attainment determination must be based upon an area's ``air quality as of the attainment date.'' Consequently, EPA will determine whether an area's air quality has met the CO NAAQS by December 31, 1995 based upon the most recent two years of air quality data entered into the Aerometric Information Retrieval System (AIRS) data base.
\1\ See memorandum from Sally L. Shaver, Director, Air Quality Strategies and Standards Division, EPA, to Regional Air Office Directors, entitled ``Criteria for Granting Attainment Date Extensions, Making Attainment Determinations, and Determinations of Failure to Attain the NAAQS for Moderate CO Nonattainment Areas,'' October 23, 1995 (Shaver memorandum).
EPA determines a CO nonattainment area's air quality status in accordance with 40 CFR 50.8 and EPA policy.<SUP>2 EPA has promulgated two NAAQS for CO: an eight-hour average concentration and a one-hour average concentration. Because there were no violations of the one-hour standard in the Clark County area in 1994 and 1995, this notice addresses only the air quality status of the Clark County area with respect to the eight-hour standard. The eight-hour CO NAAQS requires that not more than one non-overlapping eight-hour average per year per monitoring site can exceed 9.0 ppm (values below 9.5 are rounded down to 9.0 and they are not considered exceedances). The second exceedance of the eight-hour CO NAAQS at a given monitoring site within the same year constitutes a violation of the CO NAAQS.
\2\ See memorandum from William G. Laxton, Director, Technical Support Division, entitled ``Ozone and Carbon Monoxide Design Value Calculations'', June 18, 1990. See also Shaver memorandum.
C. Attainment Date Extensions If a state does not have the two consecutive years of clean data necessary to show attainment of the NAAQS, it may apply, under section 186(a)(4) of the CAA, for a one year attainment date extension. At its discretion, EPA may grant an extension if the area has: (1) measured no more than one exceedance of the CO NAAQS at any monitoring site in the nonattainment area in the year preceding the extension year, and (2) complied with the requirements and commitments pertaining to the applicable implementation plan for the area. Under section 186(a)(4), EPA may grant up to two one year extensions if these conditions have been met.
The Administrator's authority to extend attainment dates for moderate areas is discretionary. Section 186(a)(4) of the Act provides that the Administrator ``may'' extend the attainment date for areas meeting the minimum requirements specified above. The provision does not dictate or compel EPA to grant extensions to such areas. Therefore, EPA will examine the moderate area's air quality planning progress and will be disinclined to grant an attainment date extension unless a State has, in substantial part, addressed its moderate area CO planning obligations. To determine if the State has substantially met these planning requirements, EPA will review the State's attainment date extension application to assess whether the State has: (1) adopted and substantially implemented control measures to satisfy the requirements for a moderate CO nonattainment area; and, (2) that reasonable further progress is being met for the area.
If the State cannot make a sufficient demonstration that the area has met the extension criteria described above and EPA determines that the area has not demonstrated attainment of the CO NAAQS, then the area will be reclassified as serious by operation of law pursuant to section 186(b)(2) of the Act. If an extension is granted, then, at the end of the extension year, EPA will review the area's air quality data to determine if the area has attained the CO NAAQS. Recall that CO areas must have two consecutive years of clean air quality data to demonstrate attainment. Consequently, if the area measures a violation of the CO NAAQS during the extension year, the area will be unable to qualify for a second one year extension. Then, once EPA makes a finding of failure to attain the CO NAAQS, the moderate area will be reclassified as serious by operation of law. II. Today's Action In today's action, EPA proposes to find that the Clark County CO nonattainment area has met the criteria in section 186(b)(4) of the CAA, thereby qualifying for a one year attainment date extension. As a result of this finding, EPA proposes to grant a one-year extension of Clark County's moderate area attainment date from December 31, 1995 to December 31, 1996. This proposed finding is based on both EPA's review of 1994 and 1995 monitored air quality data for compliance with the CO NAAQS and EPA's review of Clark County's application for an attainment date extension. A. Ambient Air Monitoring Data The following table lists the location and dates that the eighthour CO NAAQS of 9 ppm has been exceeded in Clark County during 1994, 1995, and 1996. Although the attainment and extension criteria address the 1994 and 1995 data, the 1996 data is relevant to later discussion in this section. [[Page 41761]] Exceedances of 8-hour Carbon Monoxide National Ambient Air Quality Standard<SUP>1 in the Clark County, Nevada Nonattainment Area
1994 1995 1996 Concen. Date Concen. Date Concen. Date 2850 East Charleston Blvd...... 10.6 ppm 1/4 10.2 ppm 11/23 10.1 ppm 1/6 9.5 ppm 1/21 .......................... .......... 10.3 ppm 1/14 9.6 ppm 1/22 .......................... .......... 10.2 ppm 3/10 9.6 ppm 12/1 10.9 ppm 12/17 ppm \1\ The eight-hour carbon monoxide NAAQS is 9 parts per million. \2\ Concen. = monitored carbon monoxide concentration in parts per million.