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San Antonio: Ozone History

Background and history of San Antonio area compliance with the National Ambient Air Quality Standards (NAAQS) for ground-level ozone.

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2015 Eight-Hour Ozone Standard (2015 to Present)

On October 1, 2015, the United States Environmental Protection Agency (EPA) revised the primary and secondary eight-hour ozone standards to 0.070 parts per million (ppm). The 2015 eight-hour ozone NAAQS became effective on December 28, 2015 ( 80 FR 65292 ). On July 25, 2018, the EPA designated Bexar County as marginal nonattainment for the 2015 eight-hour ozone NAAQS, effective September 24, 2018 ( 83 FR 35136 ).

For more information on Texas' state designation recommendations for the 2015 ozone NAAQS, see:

Under a marginal classification, Bexar County is required to attain the 2015 eight-hour ozone standard by the end of 2020 to meet a September 24, 2021 attainment date. On January 15, 2020, the commission approved proposal of a federal Clean Air Act (FCAA), §179B Demonstration SIP revision that would demonstrate that the Bexar County marginal ozone nonattainment area would attain the 2015 eight-hour ozone standard by its attainment deadline “but for” anthropogenic emissions emanating from outside the United States. On January 9, 2020 the EPA issued draft guidance for the development of §179B demonstrations. On July 1, 2020, the commission adopted the Bexar County §179B Demonstration SIP revision . It was submitted to the EPA on July 13, 2020. On December 21, 2020, the EPA issued final guidance for the development of §179B demonstrations .

On June 10, 2020, the commission adopted an  emissions inventory (EI) SIP revision for the 2015 eight-hour ozone NAAQS marginal nonattainment areas, including Bexar County. It was submitted to the EPA on June 24, 2020. The revision satisfies FCAA EI reporting requirements for areas designated nonattainment for the 2015 eight-hour ozone NAAQS and also includes certification statements to confirm that emissions statement and nonattainment new source review (NSR) SIP requirements have been met for the 2015 eight-hour ozone nonattainment areas. On June 29, 2021, the EPA published final approval of the EIs for the HGB, DFW, and Bexar County 2015 eight-hour ozone nonattainment areas ( 86 FR 34139 ). On September 9, 2021, the EPA published final approval of the emissions statement and nonattainment NSR certification statements ( 86 FR 50456 ).

On October 7, 2022, the EPA reclassified Bexar County from marginal to moderate nonattainment, effective November 7, 2022 ( 87 FR 60897 ). The attainment date for the Bexar County moderate nonattainment area is September 24, 2024 with a 2023 attainment year.

2008 Eight-Hour Ozone Standard (2008 to Present)

On March 27, 2008, the EPA revised the primary and secondary eight-hour ozone NAAQS to 0.075 parts per million ( 73 FR 16436 ). On March 10, 2009, the governor recommended to the EPA that Bexar County be designated nonattainment for the 2008 ozone NAAQS (see the governor's letter to EPA region 6 ).

In September 2009, the EPA announced it would reconsider the 2008 NAAQS, and on January 19, 2010, proposed to lower the primary ozone standard to a range of 0.060–0.070 ppm, and proposed a separate secondary standard based on cumulative seasonal average ozone concentrations. On September 2, 2011, President Obama announced that he had requested the EPA withdraw the proposed reconsidered ozone standard.

In a memo dated September 22, 2011 from EPA Assistant Administrator Gina McCarthy, the EPA announced that it would proceed with initial area designations under the 2008 eight-hour ozone standard, starting with the recommendations states made in 2009 and updating them with the most current, certified air quality data (2008 through 2010).

On May 21, 2012, the EPA published in the Federal Register final designations for the 2008 eight-hour ozone NAAQS ( 77 FR 30088 ). Bexar, Comal, Guadalupe, and Wilson Counties were designated attainment/unclassifiable under the 2008 eight-hour ozone NAAQS, effective July 20, 2012.   

1997 Eight-Hour Ozone Standard (1997 to 2015)

Note: Effective April 6, 2015, the 1997 eight-hour ozone standard has been revoked in all areas, although some former 1997 eight-hour ozone nonattainment areas have continuing obligations to comply with the anti-backsliding requirements described in 40 CFR §51.1100(o).

On December 9, 2002, the Alamo Area Council of Governments , a stakeholder group for the San Antonio area, signed an Early Action Compact (EAC). On March 31, 2004, a final EAC plan was submitted to the TCEQ for incorporation into the state implementation plan (SIP).

On November 17, 2004, the commission adopted revisions to the SIP for the Austin, San Antonio, and Northeast Texas EAC areas and 30 Texas Administrative Code, Chapters 114  and 115 . The  San Antonio EAC SIP Revision consists of an eight-hour ozone attainment demonstration for the area based on the local plan submitted to TCEQ by the area in March 2004 under its EAC. This revision contains results of photochemical modeling and technical documentation in support of the attainment demonstration. As a result of these analyses, and at the request of the San Antonio local governments, the revision includes, for all four counties, changes to the rules on volatile organic compounds in degreasing and Stage I vapor recovery.

On April 2, 2008, the EPA issued final action to designate 13 EAC areas (including San Antonio) attainment for the 1997 eight-hour ozone standard, as they met all milestones of the EAC program and demonstrated attainment of the standard by December 31, 2007. The effective date of this final action was April 15, 2008. Additionally, the EPA stated that the one-hour ozone standard for each of the 13 EAC areas would be revoked one year after the effective date of their attainment designation. The San Antonio area attainment designation for the 1997 eight-hour ozone standard meant that there were no further SIP requirements for the standard as long as the area continued to monitor attainment. The 1997 eight-hour ozone standard was revoked effective April 6, 2015.

Comprehensive History of the Texas SIP

This SIP History gives a broad overview of the SIP revisions that have been submitted to the EPA by the State of Texas. Some sections may be obsolete or superseded by new revisions but have been retained for the sake of historical completeness.