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Corpus Christi: Ozone History

Background and history of Corpus Christi 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 millions (ppm). The 2015 eight-hour ozone NAAQS became effective on December 28, 2015 ( 80 FR 65292 ). On November 16, 2017, the EPA designated the majority of Texas, including San Patricio and Nueces counties, as attainment/unclassifiable for the 2015 eight-hour ozone NAAQS, with an effective date of January 16, 2018 ( 82 FR 54232 ).

2008 Eight-Hour Ozone Standard (2008 to Present)

On March 27, 2008, the EPA revised the primary and secondary eight-hour ozone standard to 0.075 ppm ( 73 FR 16436 ). On March 10, 2009, the governor recommended to the EPA that San Patricio and Nueces counties be designated attainment for the 2008 ozone standard (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 standard ( 77 FR 30088 ). San Patricio and Nueces Counties were designated attainment/unclassifiable under the 2008 eight-hour ozone NAAQS, effective July 20, 2012. 

1997 Eight-Hour Ozone Standard (1997 to Present)

In 2004, the EPA designated the Corpus Christi area attainment for the 1997 eight-hour ozone standard.  Stakeholders in Nueces and San Patricio Counties expressed a desire to develop an Ozone Flex (O3 Flex) program for the eight-hour ozone standard and sent a letter of intent to the EPA from the Mayor of Corpus Christi on October 4, 2004. In response to Corpus Christi’s initiative, the EPA issued national guidelines for the Eight-Hour O3 Flex Program on May 18, 2006, similar to the previous guidance for the One-Hour O3 Flex Program.  The purpose of the Eight-Hour O3 Flex Program was to encourage 1997 eight-hour ozone attainment areas nationwide to reduce ozone emissions to continue to meet the NAAQS for ozone. All parties signed the Eight-Hour O3 Flex five-year agreement in 2007.

One-Hour Ozone Standard

Note: In 1997, the one-hour ozone standard was replaced by the more protective eight-hour ozone standard.  The one-hour standard has been revoked in all areas, although some former one-hour ozone nonattainment areas have continuing obligations to comply with the anti-backsliding requirements described in 40 CFR 51.905(a).

Voluntary controls have helped the Corpus Christi area remain in attainment of the one-hour ozone NAAQS.

This area approached violating the one-hour ozone standard in 1995. As a result, local authorities voluntarily took the following actions to cut ozone levels by reducing emissions of volatile organic compounds:

  • use of less volatile gasoline from May through September;
  • installation of vapor recovery and control systems at marine fuel transfers and loading facilities;
  • rescheduling of uncontrolled loading activities on ozone action days until evening or until another day;
  • implementing a pollution prevention program that targeted small and large businesses;
  • promoting alternative fuels through the Clean Cities Program of the U.S. Department of Energy; and
  • promoting reformulated gas for use in large fleets by a local refiner.

As a result of these controls, the area has not exceeded the one-hour ozone standard since 1995.

Local groups such as the Pollution Prevention Partnership and Texas A&M University–Kingsville spearheaded outreach and educational efforts to maintain Corpus Christi’s attainment status. The TCEQ, EPA, and local authorities signed the One-Hour O3 Flex Plan on September 18, 2002. O3 Flex was a voluntary local approach that encouraged emission reductions to keep an area in attainment of the one-hour ozone standard, while providing the health benefits envisioned under the eight-hour ozone standard.

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.