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Air Pollution from Ozone

General information on ozone, and TCEQ planning that addresses the ozone National Ambient Air Quality Standards (NAAQS).

What is ozone?

What is ozone? How is it formed? Why should we be concerned about this air pollutant?

Latest air quality planning that addresses the ozone NAAQS

Last updated: 9/30/2016

The 2015 Ozone NAAQS

On October 1, 2015, the United States Environmental Protection Agency (EPA) revised the primary and secondary NAAQS for ozone to an eight-hour standard of 0.070 parts per million (ppm), or 70 parts per billion (ppb) (80 FR 65292) Exit the TCEQ. The Federal Clean Air Act (FCAA) requires state designation recommendations to the EPA within one year of NAAQS promulgation. By October 1, 2016, the governor of each state must recommend designations of attainment, nonattainment, or unclassifiable under the 2015 eight-hour ozone standard for all areas of the state. The EPA has not yet made final designations for the 2015 ozone standard.

For more information on the 2015 ozone standard, see:

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

Emissions Inventory (EI) SIP Revision for the 2008 Eight-Hour Ozone Standard for the Houston-Galveston-Brazoria (HGB) and Dallas-Fort Worth (DFW) Areas

On July 2, 2014, the commission adopted the EI SIP revision for the 2008 Eight-Hour Ozone Standard (Non-Rule Project No. 2013-016-SIP-NR). This SIP revision satisfies the Federal Clean Air Act (FCAA), §172 and §182 requirements for the HGB and DFW nonattainment areas under the 2008 eight-hour ozone standard. The SIP revision includes 2011 emissions inventories for ozone precursors (volatile organic compounds and nitrogen oxides) from point, area, on-road mobile, non-road mobile, and biogenic emissions source categories as the base year emissions inventories for the HGB and DFW areas. The nonattainment area base year EI submission is due no later than 24 months from the July 20, 2012 effective date of designations under the 2008 eight-hour ozone standard, July 20, 2014.

Infrastructure and Transport SIP Revision for the 2008 Ozone Standard

On December 5, 2012, the commission adopted the Federal Clean Air Act (FCAA), §110(a)(1) and (2) Infrastructure and Transport SIP Revision for the 2008 Ozone NAAQS (Non-Rule Project No. 2012-004-SIP-NR). This SIP revision outlines the requirements of FCAA, §110(a)(2)(A) through (M) and the Texas provisions supporting the requirements. These requirements include basic program elements such as enforceable emission limitations and control measures, air quality monitoring and modeling, a permitting program, adequate funding and personnel, authority under state law to carry out the plan, emissions reporting, emergency powers, public participation, and fee collection. This SIP revision also includes a technical demonstration to support that Texas meets the interstate transport requirements of FCAA, §110(a)(2)(D)(i)(I).

A public hearing was held on September 25, 2012 at the Texas Commission on Environmental Quality headquarters in Austin. The public comment period was from August 24 through September 28, 2012. Comments were submitted by the United States Environmental Protection Agency, Alamo Area Council of Governments, Public Citizen, and four individuals. 

The 2008 Ozone Standard

On March 27, 2008, the EPA lowered the primary and secondary eight-hour ozone NAAQS to 0.075 parts per million (73 FR 16436) Exit the TCEQ. On May 21, 2012, the EPA published in the Federal Register final designations for the 2008 eight-hour ozone standard (77 FR 30088Exit the TCEQ. The Dallas-Fort Worth (DFW) area was designated moderate nonattainment and the Houston-Galveston-Brazoria (HGB) area was designated marginal nonattainment. The effective date of the final rule is July 20, 2012.

On May 21, 2012, the EPA also published in the Federal Register a final rule to establish classification thresholds, establish December 31 of each relevant calendar year as the attainment date for each classification, and revoke the 1997 eight-hour ozone NAAQS for purposes of transportation conformity (77 FR 30160Exit the TCEQ.

For more information on the TCEQ's designation recommendation process for the 2008 ozone NAAQS, see:

Related Web pages and publications

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