Determination of Attainment by the Attainment Date and Clean Data Determination; California, San Joaquin Valley 1997 Annual PM2.5 Fine Particulate Matter Nonattainment Area

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R09-OAR-2025-0292; FRL-12825-01-R9]</DEPDOC> <SUBJECT> Determination of Attainment by the Attainment Date and Clean Data Determination; California, San Joaquin Valley 1997 Annual PM <E T="0735">2.5</E> Fine Particulate Matter Nonattainment Area </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) is proposing to determine that the San Joaquin Valley, California fine particulate matter (PM <E T="52">2.5</E> ) nonattainment area attained the 1997 annual PM <E T="52">2.5</E> national ambient air quality standards (NAAQS) by the December 31, 2024 applicable attainment date. This proposed determination is based on ambient air quality monitoring data from 2022 through 2024. We are also proposing to make a clean data determination (CDD) based on the 2022 through 2024 data and our evaluation of preliminary air quality monitoring data from 2025. We are taking comments on this proposal and plan to follow with a final action. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Comments must be received on or before August 15, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R09-OAR-2025-0292 at <E T="03">https://www.regulations.gov.</E> For comments submitted at <E T="03">Regulations.gov</E> , follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from <E T="03">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, please contact the person identified in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section. For the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit <E T="03">https://www.epa.gov/dockets/commenting-epa-dockets.</E> If you need assistance in a language other than English or if you are a person with a disability who needs a reasonable accommodation at no cost to you, please contact the person identified in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Ashley Graham, Geographic Strategies and Modeling Section (AIR-2-2), EPA Region IX, 75 Hawthorne Street, San Francisco, CA 94105; telephone number: (415) 972-3877; email address: <E T="03">graham.ashleyr@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document, “we,” “us,” and “our” refer to the EPA. <HD SOURCE="HD1">Table of Contents </HD> <EXTRACT> <FP SOURCE="FP-2">I. Background</FP> <FP SOURCE="FP1-2"> A. PM <E T="52">2.5</E> NAAQS </FP> <FP SOURCE="FP1-2"> B. The San Joaquin Valley PM <E T="52">2.5</E> Nonattainment Area </FP> <FP SOURCE="FP1-2">C. Clean Air Act Requirement for a Determination of Attainment</FP> <FP SOURCE="FP1-2">D. The EPA's Clean Data Policy</FP> <FP SOURCE="FP-2">II. Determination of Attainment by the Attainment Date</FP> <FP SOURCE="FP1-2">A. Monitoring Network Review, Quality Assurance, and Data Completeness</FP> <FP SOURCE="FP1-2">B. The EPA's Evaluation of Attainment</FP> <FP SOURCE="FP-2">III. Clean Data Determination</FP> <FP SOURCE="FP-2">IV. The EPA's Proposed Action</FP> <FP SOURCE="FP-2">V. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. Background</HD> <HD SOURCE="HD2"> A. PM <E T="54">2.5</E> NAAQS </HD> The Clean Air Act (CAA) requires the EPA to establish primary and secondary NAAQS for certain pervasive pollutants that “may reasonably be anticipated to endanger public health and welfare.”  <SU>1</SU> <FTREF/> The primary NAAQS is designed to protect public health with an adequate margin of safety, and the secondary NAAQS is designed to protect public welfare and the environment. The EPA has set standards for six common air pollutants, referred to as criteria pollutants. These standards represent the air quality levels an area must meet to comply with the CAA. <FTNT> <SU>1</SU>  CAA section 108(a). </FTNT> PM <E T="52">2.5</E> can be particles emitted by sources directly into the atmosphere as a solid or liquid particle (“primary PM <E T="52">2.5</E> ” or “direct PM <E T="52">2.5</E> ”) or can be particles that form in the atmosphere as a result of various chemical reactions from PM <E T="52">2.5</E> precursor emissions emitted by sources (“secondary PM <E T="52">2.5</E> ”). The EPA established each of the PM <E T="52">2.5</E> NAAQS after considering substantial evidence from numerous health studies demonstrating that serious health effects are associated with exposures to PM <E T="52">2.5</E> concentrations above such levels. Epidemiological studies have shown statistically significant correlations between elevated PM <E T="52">2.5</E> levels and premature mortality. Other important health effects associated with PM <E T="52">2.5</E> exposure include aggravation of respiratory and cardiovascular disease (as indicated by increased hospital admissions, emergency room visits, absences from school or work, and restricted activity dates), changes in lung function and increased respiratory symptoms, and new evidence for more subtle indicators of cardiovascular health. Individuals particularly sensitive to PM <E T="52">2.5</E> exposure include older adults, people with heart and lung disease, and children. <SU>2</SU> <FTREF/> <FTNT> <SU>2</SU>  EPA, Air Quality Criteria for Particulate Matter, No. EPA/600/P-99/002aF and EPA/600/P-99/002bF, October 2004. </FTNT> On July 18, 1997, the EPA revised the NAAQS for particulate matter by establishing new NAAQS for particles with an aerodynamic diameter less than or equal to a nominal 2.5 micrometers (PM <E T="52">2.5</E> ). <SU>3</SU> <FTREF/> The EPA established primary and secondary annual and 24-hour standards for PM <E T="52">2.5</E> . <SU>4</SU> <FTREF/> The EPA set the annual primary and secondary standards at 15.0 micrograms per cubic meter (μg/m <SU>3</SU> ), based on a three-year average of annual mean PM <E T="52">2.5</E> concentrations. <SU>5</SU> <FTREF/> The EPA has since strengthened the primary annual PM <E T="52">2.5</E> NAAQS;  <SU>6</SU> <FTREF/> however, the 1997 primary annual PM <E T="52">2.5</E> NAAQS remains in effect in areas designated nonattainment for that NAAQS. <SU>7</SU> <FTREF/> <FTNT> <SU>3</SU>  62 FR 38652. </FTNT> <FTNT> <SU>4</SU>  For a given air pollutant, “primary” NAAQS are those determined by the EPA as requisite to protect the public health, allowing an adequate margin of safety, and “secondary” standards are those determined by the EPA as requisite to protect the public welfare from any known or anticipated adverse effects associated with the presence of such air pollutant in the ambient air. See CAA section 109(b). </FTNT> <FTNT> <SU>5</SU>  40 CFR 50.7. </FTNT> <FTNT> <SU>6</SU>  78 FR 3086 (January 15, 2013) and 89 FR 16202 (February 7, 2024). </FTNT> <FTNT> <SU>7</SU>  40 CFR 50.13(d). </FTNT> <HD SOURCE="HD2"> B. The San Joaquin Valley PM <E T="54">2.5</E> Nonattainment Area </HD> Following promulgation of a new or revised NAAQS, the EPA is required under CAA section 107(d) to designate areas throughout the nation as attainment, nonattainment, or unclassifiable for the NAAQS. Effective April 5, 2005, the EPA established the initial air quality designations for the 1997 annual PM <E T="52">2.5</E> NAAQS, using air quality monitoring data for the three-year periods of 2001-2003 and 2002-2004. <SU>8</SU> <FTREF/> The EPA designated the San Joaquin Valley as nonattainment for the 1997 annual PM <E T="52">2.5</E> NAAQS. <SU>9</SU> <FTREF/> <FTNT> <SU>8</SU>  70 FR 944 (January 5, 2005). </FTNT> <FTNT> <SU>9</SU>  40 CFR 81.305. </FTNT> The San Joaquin Valley PM <E T="52">2.5</E> nonattainment area encompasses over 23,000 square miles and includes all or part of eight counties: San Joaquin, Stanislaus, Merced, Madera, Fresno, Tulare, Kings, and the valley portion of Kern. <SU>10</SU> <FTREF/> The area is home to four million people and is one of the nation's leading agricultural regions. Stretching over 250 miles from north to south and averaging 80 miles wide, it is partially enclosed by the Coast Mountain range to the west, the Tehachapi Mountains to the south, and the Sierra Nevada range to the east. <FTNT> <SU>10</SU>  For a precise description of the geographic boundaries of the San Joaquin Valley nonattainment area, see 40 CFR 81.305. </FTNT> The California Air Resources Board (CARB) is the state agency responsible for the adoption and submission to the EPA of California state implementation plan (SIP) submissions. Under California law, air districts in California are generally responsible for the development of regional air quality plans. For the San Joaquin Valley area, the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD or “District”) develops and adopts air quality management plans to address CAA planning requirements applicable to the region. 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