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

<RULE> ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R09-OAR-2025-0070; FRL-12637-03-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> Final determination. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is finalizing our determination 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 determination is based on quality-assured and certified ambient air quality monitoring data from 2022 through 2024. We are also finalizing a determination that the requirement for the State to have contingency measures for reasonable further progress (RFP) and attainment for the 2008 ozone NAAQS no longer applies for this area. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> This determination is effective on September 22, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> The EPA has established a docket for this action under Docket ID No. EPA-R09-OAR-2025-0070. All documents in the docket are listed on the <E T="03">https://www.regulations.gov</E> website. Although listed in the index, some information is not publicly available, <E T="03">e.g.,</E> Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the internet and will be publicly available only in hard copy form. Publicly available docket materials are available through <E T="03">https://www.regulations.gov,</E> or please contact the person identified in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section for additional availability information. 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. Summary of Proposed Action</FP> <FP SOURCE="FP-2">II. Public Comments and EPA Responses</FP> <FP SOURCE="FP-2">III. Final Determination</FP> <FP SOURCE="FP-2">IV. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. Summary of Proposed Action</HD> On March 21, 2025, the EPA proposed to determine that the Sacramento Metro area attained the 2008 ozone national ambient air quality standards (NAAQS) by its December 31, 2024 attainment date. <SU>1</SU> <FTREF/> On the same date, we issued an interim final determination to stay and defer sanctions associated with a previous disapproval of the State's submittal addressing contingency measures requirements for the Sacramento Metro area for the 2008 ozone NAAQS. <SU>2</SU> <FTREF/> <FTNT> <SU>1</SU>  90 FR 13316 (March 21, 2025). </FTNT> <FTNT> <SU>2</SU>  90 FR 13288 (March 21, 2025). </FTNT> As discussed in section II.A of our proposed determination, an area is considered to have attained the 2008 ozone standards if there are no violations of the standards, 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 design value ( <E T="03">i.e.,</E> 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>3</SU> <FTREF/> <FTNT> <SU>3</SU>  40 CFR 50.15 and 40 CFR part 50, appendix P. </FTNT> The EPA proposed this determination to fulfill our statutory obligation under Clean Air Act (CAA or “Act”) section 181(b)(2) to determine whether the area attained the 2008 ozone NAAQS by its attainment date. Our proposed determination was based on complete, quality-assured and certified ozone air quality monitoring data for the 2022-2024 calendar years. A summary of the air quality monitoring data for these years is provided in Table 1. <GPOTABLE COLS="6" OPTS="L2,nj,i1" CDEF="xs72,r50,10,10,10,12"> <TTITLE> Table 1—Sacramento Metro Area Fourth High 8-Hour Ozone Average Concentrations and Design Values ( <E T="01">ppm</E> ) for 2022-2024 </TTITLE> <CHED H="1">AQS site ID</CHED> <CHED H="1">Site name</CHED> <CHED H="1">4th Highest daily maximum</CHED> <CHED H="2">2022</CHED> <CHED H="2">2023</CHED> <CHED H="2">2024</CHED> <CHED H="1"> Design value (2022-2024) </CHED> <ROW EXPSTB="05" RUL="s"> <ENT>0.064</ENT> <ENT>0.065</ENT> <ENT>0.074</ENT> <ENT>0.072</ENT> <ENT>0.072</ENT> <ENT>0.072</ENT> </ROW> <ROW RUL="s"> <ENT I="01">06-017-2004</ENT> <ENT>Placerville—Canal Street</ENT> <ENT>0.066</ENT> <ENT>0.067</ENT> <ENT>0.067</ENT> <ENT>0.066</ENT> </ROW> <ROW EXPSTB="05" RUL="s"> <ENT I="21"> <E T="02">PLACER COUNTY</E> </ENT> </ROW> <ROW EXPSTB="00"> <ENT I="01">06-061-0003</ENT> <ENT>Auburn—Atwood</ENT> <ENT>0.075</ENT> <ENT>0.064</ENT> <ENT>0.079</ENT> <ENT>0.072</ENT> </ROW> <ROW> <ENT I="01">06-061-0004</ENT> <ENT>Colfax—City Hall</ENT> <ENT>0.070</ENT> <ENT>0.067</ENT> <ENT>0.067</ENT> <ENT>0.068</ENT> </ROW> <ROW> <ENT I="01">06-061-0006</ENT> <ENT>Roseville—N Sunrise Ave</ENT> <ENT>0.070</ENT> <ENT>0.077</ENT> <ENT>0.077</ENT> <ENT>0.074</ENT> </ROW> <ROW RUL="s"> <ENT I="01">06-061-2003</ENT> <ENT>Lincoln—2885 Moore Road</ENT> <ENT>0.066</ENT> <ENT>0.060</ENT> <ENT>0.063</ENT> <ENT>0.063</ENT> </ROW> <ROW EXPSTB="05" RUL="s"> <ENT I="21"> <E T="02">SACRAMENTO COUNTY</E> </ENT> </ROW> <ROW EXPSTB="00"> <ENT I="01">06-067-0002</ENT> <ENT>North Highlands—Blackfoot Way</ENT> <ENT>0.070</ENT> <ENT>0.077</ENT> <ENT>0.080</ENT> <ENT>0.075</ENT> </ROW> <ROW> <ENT I="01">06-067-0010</ENT> <ENT>Sacramento—T Street</ENT> <ENT>0.065</ENT> <ENT>0.066</ENT> <ENT>0.069</ENT> <ENT>0.066</ENT> </ROW> <ROW> <ENT I="01">06-067-0011</ENT> <ENT>Elk Grove—Bruceville</ENT> <ENT>0.058</ENT> <ENT>0.050</ENT> <ENT>0.048</ENT> <ENT>0.052</ENT> </ROW> <ROW> <ENT I="01">06-067-0012</ENT> <ENT>Folsom</ENT> <ENT>0.070</ENT> <ENT>0.071</ENT> <ENT>0.065</ENT> <ENT>0.068</ENT> </ROW> <ROW RUL="s"> <ENT I="01">06-067-5003</ENT> <ENT>Sloughhouse</ENT> <ENT>0.074</ENT> <ENT>0.063</ENT> <ENT>0.061</ENT> <ENT>0.058</ENT> <ENT>0.060</ENT> </ROW> <ROW EXPSTB="05" RUL="s"> <ENT I="21"> <E T="02">YOLO COUNTY</E> </ENT> </ROW> <ROW EXPSTB="00"> <ENT I="01">06-113-0004</ENT> <ENT>Davis—UCD Campus</ENT> <ENT>0.059</ENT> <ENT>0.065</ENT> <ENT>0.063</ENT> <ENT>0.062</ENT> </ROW> <ROW> <ENT I="01">06-113-1003</ENT> <ENT>Woodland—Gibson Road</ENT> <ENT>0.066</ENT> <ENT>0.062</ENT> <ENT>0.064</ENT> <ENT>0.064</ENT> </ROW> <TNOTE> <SU>a</SU>  The required annual 75 percent completeness criterion was not met, therefore the annual 4th highest daily maximum values were not provided. </TNOTE> <TNOTE> <SU>b</SU>  The invalid Echo Summit design value was a result of incomplete data capture primarily due to site access challenges for the entire month of April and part of May in the years 2022 through 2024. To resolve the access issues, CARB submitted a site closure request for the Echo Summit ozone monitor to EPA on February 10, 2025, and requested a new ozone monitor at the South Lake Tahoe—Sandy Way monitoring site, with a proposed start date of February 10, 2025. The EPA approved CARB's site closure request on April 15, 2025. See letter dated April 15, 2025, from Dena Vallano, Manager, Monitoring and Analysis Section, EPA Region IX, to Michael Miguel, Assistant Division Chief, Monitoring and Laboratory Division, CARB, dated April 15, 2025. </TNOTE> <TNOTE> <SU>c</SU>  The design value for the North Highlands—Blackfoot Way site is invalid due to missing data from August 2022 through December 2024. SMAQMD lost the lease to the North Highlands—Blackfoot Way monitoring site and were forced to shut down the monitor on August 1, 2022. SMAQMD is looking to secure a new location for the site. </TNOTE> <TNOTE> <SU>d</SU>  The Sloughhouse design value is invalid due to null coded data in AQS with poor quality assurance results from July 2023 through April 2024. </TNOTE> <TNOTE>Invalid design values and annual 4th highest daily maximum values can be found in the file titled “SFNA O3 Design Value Report 2008-2024.pdf” that is included in the docket for this action.</TNOTE> <TNOTE>Source: EPA, AQS Design Value (AMP480), Report Request ID: 2260106, February 6, 2025.</TNOTE> </GPOTABLE> Our proposed determination includes additional information about ozone air pollution, the NAAQS, and the statutory and regulatory bases for making a determination of attainment. The proposed determination also includes information about the Sacramento Metro nonattainment area, the Tribes whose lands are located within the nonattainment area, and the ozone air quality data considered for the determination (information about the monitoring network, the data certification process, data completeness considerations and other relevant information). In our proposed rulemaking, we also proposed to determine that, if we finalized our determination of attainment by the attainment date, then the requirement for the area to have contingency measures for failure to meet RFP and ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 42k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━