Extension of the Attainment Date and Determination of Attainment by the Attainment Date of the Uinta Basin Marginal Nonattainment Area Under the 2015 Ozone National Ambient Air Quality Standards

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R08-OAR-2024-0001; FRL-11838-01-R8]</DEPDOC> <SUBJECT>Extension of the Attainment Date and Determination of Attainment by the Attainment Date of the Uinta Basin Marginal Nonattainment Area Under the 2015 Ozone National Ambient Air Quality Standards</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Proposed rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA or Agency) is proposing two Clean Air Act (CAA) actions related to the attainment date for the Uinta Basin (Basin), Utah Marginal nonattainment area under the 2015 Ozone National Ambient Air Quality Standards (NAAQS). First, the Agency is proposing to grant a second 1-year extension of the attainment date for the area. This action would extend the Marginal area attainment date for this area from August 3, 2022, to August 3, 2023. Second, the Agency is proposing to determine that the area attained the standard by the extended attainment date of August 3, 2023, based on certified ozone monitoring data from 2020-2022. This action, if finalized, will fulfill the EPA's statutory obligation to determine whether the Uinta Basin Marginal ozone nonattainment area attained the NAAQS by the attainment date through publication in the <E T="04">Federal Register</E> . </SUM> <DATES> <HD SOURCE="HED">DATES:</HD> Written comments must be received on or before May 10, 2024. </DATES> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R08-OAR-2024-0001, to the Federal Rulemaking Portal: <E T="03">www.regulations.gov.</E> Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from <E T="03">www.regulations.gov.</E> The EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission ( <E T="03">i.e.,</E> on the web, cloud, or other file sharing system). For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit <E T="03">http://www2.epa.gov/dockets/commenting-epa-dockets.</E> <E T="03">Docket:</E> All documents in the docket are listed in the <E T="03">www.regulations.gov</E> index. Although listed in the index, some information is not publicly available, <E T="03">e.g.,</E> CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available electronically in <E T="03">www.regulations.gov.</E> To reduce the risk of COVID-19 transmission, for this action we do not plan to offer hard copy review of the docket. Please email or call the person listed in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section if you need to make alternative arrangements for access to the docket. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Amanda Brimmer, Air and Radiation Division, EPA, Region 8, Mailcode 8ARD-IO, 1595 Wynkoop Street, Denver, Colorado, 80202-1129, (303) 312-6323, <E T="03">brimmer.amanda@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> In this document “we,” “us,” and “our” mean the EPA. <HD SOURCE="HD1">Overview and Basis of Proposal</HD> <HD SOURCE="HD2">A. Overview of Proposal</HD> Under CAA section 181(b)(2), the EPA is required to determine whether areas designated as nonattainment for an ozone NAAQS attain the standard by the applicable attainment date, and to take certain steps for areas that fail to attain. Because the ozone NAAQS is a concentration-based standard, a determination of attainment is based on a nonattainment area's design value (DV) as of the attainment date. <SU>1</SU> <FTREF/> In this proposal the EPA is addressing the 2015 ozone NAAQS. <SU>2</SU> <FTREF/> <FTNT> <SU>1</SU>  A design value is a statistic used to compare data collected at an ambient air quality monitoring site to the applicable NAAQS to determine compliance with the standard. The DV for the 2015 ozone NAAQS is the 3-year average of the annual fourth highest daily maximum 8-hour average ozone concentration. The DV is calculated for each air quality monitor in an area, and the DV for an area is the highest DV among the individual monitoring sites located in the area. </FTNT> <FTNT> <SU>2</SU>  Because the 2015 primary and secondary NAAQS for ozone are identical, for convenience, the EPA refers to them in the singular as “the 2015 ozone NAAQS” or as “the standard.” </FTNT> On March 29, 2021, the State of Utah requested a 1-year extension of the Marginal attainment date for the Uinta Basin. The Ute Indian Tribe (UIT) subsequently requested an extension on May 25, 2021. Based on EPA's evaluation, the criteria for an attainment date extension had been met, and in October 2022, EPA granted the extension, making the new attainment date August 3, 2022. <SU>3</SU> <FTREF/> On March 29, 2022, the State of Utah requested a second one-year extension of the Marginal attainment date for the Uinta Basin nonattainment area, which would extend the attainment date to August 3, 2023. <SU>4</SU> <FTREF/> On December 20, 2022, the UIT also requested a second one-year extension. <FTNT> <SU>3</SU>   <E T="03">See</E> Final rule, Determinations of Attainment by the Attainment Date (DAAD), Extensions of the Attainment Date, and Reclassification of Areas Classified as Marginal for the 2015 Ozone National Ambient Air Quality Standards, 87 FR 60897 (Oct. 7, 2022). </FTNT> <FTNT> <SU>4</SU>   <E T="03">See</E> letter dated March 30, 2022, from Utah Department of Environmental Quality (UDEQ) Executive Director Kim Shelley to U.S. EPA Region 8 Regional Administrator KC Becker; and letter dated December 20, 2022, from Ute Indian Tribe Chairman Shaun Chapoose to U.S. EPA Region 8 Regional Administrator KC Becker. </FTNT> Under the EPA regulations at 40 CFR part 50, appendix U, the 2015 ozone NAAQS is attained at a site when the 3-year average of the annual fourth highest daily maximum 8-hour average ambient air quality ozone concentration ( <E T="03">i.e.,</E> DV) does not exceed 0.070 ppm. When the DV does not exceed 0.070 ppm at each ambient air quality monitoring site within the area, the area is deemed to be attaining the ozone NAAQS. For this area, which is classified as Marginal nonattainment for the 2015 ozone NAAQS, the attainment date was August 3, 2022, and the proposed extended attainment date would be August 3, 2023. Because the DV is based on the three most recent, complete calendar years of data, attainment must occur no later than December 31 of the year before the attainment date. Therefore, in light of our proposed extension of the attainment date, the proposed determination of attainment is based upon the complete, quality-assured, and certified ozone monitoring data from calendar years 2019 through 2022. Table 1 provides a summary of the DVs and the EPA's proposed air quality-based determinations for the area addressed in this action. While the 2019-2021 DV does not show attainment, the two-year average of 2020-2021 qualifies the region for a second 1-year attainment date extension. <SU>5</SU> <FTREF/> Based on the 2020-2022 DV, the region did not exceed 0.070 ppm, and EPA proposes to find that the area attained by the proposed new attainment date. <FTNT> <SU>5</SU>  To qualify for a second 1-year extension, an area's fourth highest daily maximum 8-hour value, averaged over both the original attainment year and the first extension year, must be 0.070 ppm or less (40 CFR 51.1307(a)(2)). As of July 18, 2022, the Uinta Basin area's certified 2020 and 2021 ozone data show that the maximum two-year average design value for 2020-2021 is 0.069 ppm. This is based on 2020 and 2021 ozone values at the two key monitors in the region (AQS Site 490472002 which had fourth highest daily maximum 8-hour value for 2020 at 0.066 ppm, and AQS Site 490472003 which had fourth highest daily maximum 8-hour value for 2021 at 0.072 ppm, which averaged is 0.069 ppm.). </FTNT> <GPOTABLE COLS="5" OPTS="L2,i1" CDEF="15C,15C,r100,15C,r100"> <TTITLE> Table 1—Uinta Basin 2015 Ozone NAAQS Marginal Nonattainment Area Evaluation Summary  <SU>6</SU> </TTITLE> <CHED H="1">2019-2021 DV (ppm)</CHED> <CHED H="1">Area failed to attain 2015 NAAQS but state requested 2nd 1-year attainment date extension based on average 2020-2021 4th highest daily maximum 8-hr average ≤0.070 ppm</CHED> <ENT I="01">0.078</ENT> <ENT>0.069</ENT> <ENT>Yes</ENT> <ENT>0.067</ENT> <ENT>Yes.</ENT> </ROW> </GPOTABLE> <HD SOURCE="HD2"> B. What is <FTREF/> the background for the proposed actions? </HD> <FTNT> <SU>6</SU>  The 1st through 4th highest 8-hour average ozone concentrations at each monitor for each year can be found at EPA's Outdoor Air Quality Data, Monitor Values Report, <E T="03">https://www.epa.gov/outdoor-air-quality-data/monitor-values-report.</E> These are AirData reports are produced from a direct query of the Air Quality System (AQS) Data Mart. The data represent the best and most recent information available to EPA from state agencies. However, some values may be absent due to incomplete reporting, and some values may change due ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 48k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━