Determination of Attainment by the Attainment Date; 2008 8-Hour Ozone Standards; California; Sacramento Metro Area

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R09-OAR-2025-0070; FRL-12637-02-R9]</DEPDOC> <SUBJECT>Determination of Attainment by the Attainment Date; 2008 8-Hour Ozone Standards; California; Sacramento Metro Area</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Proposed determination. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is proposing to determine that the Sacramento Metro, California area attained the 2008 8-hour ozone national ambient air quality standards (NAAQS) by its December 31, 2024 attainment date. This proposed determination is based on quality-assured and certified ambient air quality monitoring data from 2022 through 2024. If we finalize this determination as proposed, the requirement for the State to have contingency measures for reasonable further progress (RFP) and attainment for the 2008 ozone NAAQS will no longer apply for this area. We are taking comments on this proposal and plan to follow with a final action. Elsewhere in this <E T="04">Federal Register</E> , we are making an interim final determination that will stay and defer the imposition of Clean Air Act (CAA or “Act”) sanctions associated with a disapproval action related to the contingency measures requirement for this area. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Comments must be received on or before April 21, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R09-OAR-2025-0070 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> Laura Lawrence, EPA Region IX, 75 Hawthorne St., San Francisco, CA 94105; phone: (415) 972-3407; email: <E T="03">lawrence.laura@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. Regulatory Context</FP> <FP SOURCE="FP1-2">B. The Sacramento Metro Area</FP> <FP SOURCE="FP-2">II. EPA Analysis</FP> <FP SOURCE="FP1-2">A. Applicable Statutory and Regulatory Provisions</FP> <FP SOURCE="FP1-2">B. Determination of Attainment or Failure To Attain</FP> <FP SOURCE="FP1-2">C. Monitoring Network Considerations</FP> <FP SOURCE="FP1-2">D. Data Considerations</FP> <FP SOURCE="FP1-2">E. Effects of This Proposed Determination</FP> <FP SOURCE="FP-2">III. Action Summary</FP> <FP SOURCE="FP-2">IV. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. Background</HD> <HD SOURCE="HD2">A. Regulatory Context</HD> The 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, including ozone. 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> Ground-level ozone pollution is formed from the reaction of volatile organic compounds (VOC) and oxides of nitrogen (NO <E T="52">X</E> ) in the presence of sunlight. <SU>2</SU> <FTREF/> These two pollutants, referred to as ozone precursors, are emitted by many types of sources, including on- and off-road motor vehicles and engines, power plants and industrial facilities, and smaller area sources such as lawn and garden equipment and paints. <FTNT> <SU>2</SU>  The State of California refers to reactive organic gases (ROG) rather than VOC in some of its ozone related SIP submissions. As a practical matter, ROG and VOC refer to the same set of chemical constituents, and for the sake of simplicity, we refer to this set of gases as VOC in this determination notice. </FTNT> Scientific evidence indicates that adverse public health effects occur following exposure to ozone, particularly in children and adults with lung disease. Breathing air containing ozone can reduce lung function and inflame airways, which can increase respiratory symptoms and aggravate asthma or other lung diseases. <SU>3</SU> <FTREF/> <FTNT> <SU>3</SU>  EPA, Health Effects of Ozone Pollution, available at <E T="03">https://www.epa.gov/ground-levelozone-pollution/health-effects-ozone-pollution.</E> </FTNT> In March 2008, the EPA strengthened the ozone NAAQS, establishing primary and secondary 8-hour ozone standards at a level of 0.075 parts per million (ppm) (“2008 ozone NAAQS”). <SU>4</SU> <FTREF/> The numerical level of the NAAQS had previously been set at 0.08 ppm. <SU>5</SU> <FTREF/> Section 107(d) of the CAA requires the EPA to designate an area “nonattainment” if it is violating the standards or if it has sources contributing to a violation of the standards in a nearby area. For ozone standards, the EPA classifies nonattainment areas as “Marginal,” “Moderate,” “Serious,” “Severe,” or “Extreme,” depending upon ambient air monitoring values at the time of designation. <SU>6</SU> <FTREF/> An ozone nonattainment area with a higher classification is subject to more stringent CAA planning and control requirements than lower classification areas, but the state is provided more time to attain the NAAQS. <SU>7</SU> <FTREF/> <FTNT> <SU>4</SU>  73 FR 16436 (March 27, 2008). </FTNT> <FTNT> <SU>5</SU>  In October 2015, the EPA further strengthened the primary and secondary eight-hour ozone NAAQS from 0.075 ppm to 0.070 ppm. 80 FR 65291 (October 26, 2015). This action relates only to the 2008 ozone NAAQS. </FTNT> <FTNT> <SU>6</SU>  See CAA section 181(a)(1). </FTNT> <FTNT> <SU>7</SU>  See, generally, subpart 2 of part D of title I of the CAA. </FTNT> An area is considered to have attained the 2008 ozone standard if there are no violations of the standard, as determined in accordance with 40 CFR 50.15, based on three consecutive years of complete, quality-assured, and certified monitoring data. A violation of the NAAQS occurs when the ambient ozone air quality monitoring data show that the 3-year average of the annual fourth-highest daily maximum 8-hour average ozone concentrations at an ozone monitor is greater than 0.075 ppm. <SU>8</SU> <FTREF/> <FTNT> <SU>8</SU>  40 CFR 50.15 and 40 CFR part 50, Appendix P. </FTNT> <HD SOURCE="HD2">B. The Sacramento Metro Area</HD> The EPA designated the Sacramento Metro area as nonattainment for the 2008 ozone NAAQS on May 21, 2012, and classified the area as “Severe-15.”  <SU>9</SU> <FTREF/> The area's applicable attainment date for the 2008 ozone NAAQS is December 31, 2024. <SU>10</SU> <FTREF/> <FTNT> <SU>9</SU>  77 FR 30088 (May 21, 2012). </FTNT> <FTNT> <SU>10</SU>  See 85 FR 68509, 68510 (October 29, 2020). </FTNT> The Sacramento Metro area consists of Sacramento and Yolo counties and portions of El Dorado, Placer, Solano and Sutter counties, and is under the jurisdiction of the California Air Resources Board (CARB) and the following regional air pollution control districts: the El Dorado County Air Quality Management District (EDCAQMD), the Feather River Air Quality Management District (FRAQMD), the Placer County Air Pollution Control District (PCAPCD), the Sacramento Metropolitan Air Quality Management District (SMAQMD), and the Yolo-Solano Air Quality Management District (YSAQMD) (collectively, “Districts”). <SU>11</SU> <FTREF/> The nonattainment area also includes Tribal lands under the jurisdiction of the Shingle Springs Band of Miwok Indians, Shingle Springs Rancheria (Verona Track), California; the United Auburn Indian Community of the Auburn Rancheria of California, and the Yocha Dehe Wintun Nation, California. <FTNT> <SU>11</SU>  For a precise description of the geographic boundaries of the Sacramento Metro Area for the 2008 ozone NAAQS, refer to 40 CFR 81.305. Specifically included portions are the eastern portion of Solano County, the western portions of Placer and El Dorado counties outside of the Lake Tahoe Basin, and the southern portion of Sutter County. </FTNT> CARB is the state agency responsi ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 41k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━