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State Ozone Designation Recommendation

This page provides information about Texas recommendations to the United States Environmental Protection Agency (EPA) on ozone nonattainment designations.

The SIP files on this page are hosted by the Texas Records and Information Locator (TRAIL) web archive . If you need assistance with a file, please contact siprules@tceq.texas.gov.

El Paso County Nonattainment Designation for the 2015 Eight-Hour Ozone National Ambient Air Quality Standard (NAAQS)*

On November 30, 2021, the EPA published a final nonattainment designation for the 2015 eight-hour ozone NAAQS for El Paso County, effective December 30, 2021. The EPA expanded the Sunland Park, New Mexico marginal nonattainment area to include all of El Paso County and renamed the area as the “El Paso-Las Cruces, Texas-New Mexico nonattainment area."

*On June 30, 2023, the D.C. Circuit Court of Appeals reversed the nonattainment designation for El Paso County, finding that the EPA’s action was impermissibly retroactive.

Remanded El Paso County Designation for the 2015 Eight-Hour Ozone NAAQS

In August 2018, the City of Sunland Park, New Mexico and environmental petitioners challenged the EPA’s attainment/unclassifiable designation for El Paso County. On July 10, 2020, the D.C. Circuit Court of Appeals issued its opinion to remand (without vacatur) the El Paso County attainment designation to the EPA and require the EPA to issue a revised El Paso County designation for the 2015 eight-hour ozone NAAQS as expeditiously as practicable. On December 21, 2020, the TCEQ submitted supplemental information to the EPA in support of retaining El Paso County’s original attainment designation. The  EPA sent a 120-day letter to Texas on May 25, 2021 notifying the governor that the EPA intends to modify the designation for El Paso County to nonattainment as part of the existing Doña Ana partial-county (Sunland Park) ozone nonattainment area. On July 26, 2021, the TCEQ submitted a response requesting that the EPA not modify El Paso County’s existing attainment/unclassifiable designation consistent with all the information submitted by the state.

Round 3 Area Designations for the 2015 Eight-Hour Ozone NAAQS (San Antonio)

On July 25, 2018, the EPA published final designations for the San Antonio area, designating Atascosa, Bandera, Comal, Guadalupe, Kendall, Medina, and Wilson Counties as attainment/unclassifiable and designating Bexar County as nonattainment with a marginal classification with an effective date of September 24, 2018.

For more information regarding EPA designations for the 2015 eight-hour ozone NAAQS, please visit the EPA's Ozone Designations Regulatory Actions  webpage.

Round 2 Area Designations for the 2015 Eight-Hour Ozone NAAQS

On June 4, 2018, the EPA published final designations for all remaining areas of Texas except the eight counties comprising the San Antonio area. The EPA finalized nonattainment designations for a nine-county DFW area (Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Tarrant, and Wise Counties) and a six-county HGB area (Brazoria, Chambers, Fort Bend, Galveston, Harris, and Montgomery Counties). The EPA classified both nonattainment areas as marginal. The EPA designated all remaining counties as attainment/unclassifiable.

Texas Response to the EPA's 120-day Letter for San Antonio Area Designations

On March 19, 2018, the EPA sent a  120-day letter  to Texas proposing to designate Atascosa, Bandera, Comal, Guadalupe, Kendall, Medina, and Wilson Counties as attainment/unclassifiable. The EPA is proposing to modify Texas’ recommendation of attainment for Bexar County and intends to designate all or portions of Bexar County as “at best” unclassifiable. Additional information in response to the 120-day letter was submitted by the governor to the EPA on May 11, 2018. Designations for the San Antonio area are expected to be finalized by July 17, 2018.

Texas Responses to the EPA's 120-day Letter and Request for Additional Information Regarding the San Antonio Area for Remaining Area Designations Under the 2015 Eight-Hour Ozone NAAQS

On December 22, 2017 , the EPA sent 120-day letters responding to state recommendations for remaining area designations under the 2015 eight-hour ozone NAAQS. The EPA proposed nonattainment designations for Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, Tarrant, and Wise Counties in the DFW area and Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller Counties in the HGB area. Information from states was due to the EPA by February 28, 2018. On January 19, 2018, the EPA sent a follow-up letter requesting that Texas submit any additional information regarding designation recommendations for the San Antonio area by February 28, 2018.

On February 28, 2018, Texas submitted a response to the EPA's 120-day letter, updating designation recommendations for Rockwall, Liberty, and Waller Counties to attainment. Texas also submitted a response to the EPA's request for additional information regarding the San Antonio area, recommending that Bexar County be designated attainment.

Round 1 Area Designations for the 2015 Eight-Hour Ozone NAAQS

On November 6, 2017, the EPA issued "attainment/unclassifiable" designations for most areas of Texas meeting the 2015 eight-hour ozone NAAQS. The EPA intends to address designations for the remaining areas in Texas in a separate future action.

Updated State Designation Recommendations for the 2015 Eight-Hour Ozone NAAQS

A letter updating the September 30, 2016 designation recommendation based on final 2016 monitoring data and information from exceptional events was submitted by the TCEQ to the EPA on August 23, 2017, updating the recommendations for Hood and El Paso Counties to attainment. A letter from the governor urging that no new areas in Texas be designated nonattainment for the 2015 eight-hour ozone NAAQS was submitted to the EPA on September 27, 2017. 

EPA Withdraws Extended Deadline for Promulgating Designations for the 2015 Eight-Hour Ozone NAAQS

On June 28, 2017, the EPA announced that it would be using its authority under the federal Clean Air Act (FCAA) to extend the deadline for promulgating initial area designations for the 2015 eight-hour ozone NAAQS by one year, to October 1, 2018 ( 82 FR 29246 ). However on August 10, 2017, the EPA announced that it is withdrawing the extension and that the deadline for the EPA to promulgate initial designations for the 2015 eight-hour ozone NAAQS is October 1, 2017 ( 82 FR 37318 ).

State Designation Recommendations for the 2015 Eight-Hour Ozone NAAQS

On August 3, 2016, the commission approved designation recommendations for the 2015 eight-hour ozone NAAQS (Non-Rule Project No. 2016-009-SIP-NR). Staff recommends that all counties in the State of Texas with regulatory ozone monitors exceeding the revised NAAQS based on certified 2013 through 2015 monitoring data, as well as all counties designated nonattainment for the 2008 eight-hour ozone NAAQS, be designated nonattainment for the 2015 eight-hour ozone NAAQS. This would result in new nonattainment designations for Bexar, Hood, and El Paso Counties. Additionally, staff recommends that all counties in the State of Texas that have regulatory ozone monitors with complete data meeting the revised NAAQS, and are not currently located in an area designated nonattainment for the 2008 eight-hour ozone NAAQS, be designated attainment. Staff recommends that all other counties of the state be designated as unclassifiable/attainment. Finally, staff recommends that the nonattainment designation recommendations for Bexar, Hood, and El Paso Counties be revised to attainment should these counties meet the NAAQS with a 2016 design value of 70 parts per billion or less. The recommended designations were provided to the governor for his consideration and were submitted to the EPA on September 30, 2016.

Public Comment Period: State Designation Recommendations for the 2015 Eight-Hour Ozone NAAQS

The TCEQ's Air Quality Division (AQD) solicited public comment on potential area designations and boundaries under the 2015 eight-hour ozone NAAQS for consideration in developing state designation recommendations due to the EPA by October 1, 2016. The public comment period closed on April 15, 2016.

The TCEQ’s AQD took comment on a potential recommendation that counties with regulatory ozone monitors measuring over the 2015 eight-hour ozone NAAQS of 70 parts per billion (ppb) be designated nonattainment based on the latest available ozone monitoring data from 2013 through 2015. In addition, areas currently designated as nonattainment for the 2008 eight-hour ozone standard would be recommended as nonattainment areas for the 2015 eight-hour ozone standard. Based on 2015 ozone monitoring design values, new nonattainment counties under the 2015 eight-hour ozone NAAQS would be Bexar (78 ppb), Hood (73 ppb), and El Paso (71 ppb). The recommendation under consideration also included all other counties in Texas with regulatory monitors with ozone design values below the 2015 eight-hour ozone NAAQS being designated attainment including: Bell, Brewster, Cameron, Gregg, Harrison, Hidalgo, Hunt, Jefferson, McLennan, Navarro, Nueces, Orange, Polk, Randall, Smith, Travis, Victoria, and Webb. All other counties not having a regulatory ozone monitor would be recommended to have a designation of unclassifiable/attainment consistent with historical EPA designation practices.

Reference Documents:

2015 Eight-Hour Ozone Standard

On October 1, 2015, the EPA revised the primary and secondary eight-hour NAAQS for ozone from 0.075 parts per million (ppm) to 0.070 ppm, or 70 parts per billion (ppb). Information about the revised ozone standard can be viewed at the EPA's 2015 NAAQS for Ozone  webpage. The FCAA requires state designation recommendations to the EPA within one year of NAAQS promulgation. By October 1, 2016, the governor of each state had to recommend designations of attainment, nonattainment, or unclassifiable under the 2015 eight-hour ozone standard for all areas of the state. The EPA was initially expected to make final designations by October 1, 2017.

2008 Eight-Hour Ozone Standard Update

On September 22, 2011, the EPA announced it would move forward with implementation of its 2008 eight-hour ozone standard.

On October 31, 2011, the governor of Texas submitted a letter to the EPA Region 6 with the state's updated recommendation covering designations under the federal 2008 eight-hour ozone standard. The letter updates the governor's March 10, 2009 recommendations.

On December 9, 2011, the EPA Region 6 sent a letter to governors responding to the state designation recommendations. States were given until February 29, 2012 to respond to the EPA.

On December 20, 2011, the EPA published in the Federal Register the dates for a public comment period covering the EPA's December 9 responses to states ( 76 FR 78872 ).

On January 11, 2012, the Texas Commission on Environmental Quality (TCEQ) submitted written comments to the EPA in response to the EPA's December 20, 2011, Federal Register notice.

On February 10, 2012, the TCEQ submitted a recommendation to the governor that he ask the EPA to reverse its plan to expand the DFW and HGB ozone nonattainment areas pursuant to the EPA's 2008 eight-hour ozone standard because there is insufficient scientific justification for the EPA's proposed expansion of these two ozone nonattainment areas. The governor submitted the letter and technical analysis to the EPA on February 29, 2012.

On May 21, 2012, the EPA published in the Federal Register final designations for the 2008 eight-hour ozone standard ( 77 FR 30088 ). 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 30160 ).

2010 Proposed Ozone Standards

On January 6, 2010, the EPA proposed a primary eight-hour ozone air quality standard within the range of 0.060 to 0.070 parts per million (ppm) and a separate seasonal secondary standard within the range of 7 to 15 ppm-hours using a cumulative peak-weighted index. The primary standard protects people while the secondary standard protects welfare such as sensitive ecosystems and forests. The EPA's proposal, published in the Federal Register on January 19, 2010, was a reconsideration of the 2008 eight-hour standard of 0.075 ppm ( 75 FR 2938 ).

The TCEQ provided written  comments  on March 22, 2010.

The TCEQ's Air Quality Division hosted informational public meetings in June and July of 2010 on the EPA's proposed 2010 ozone air quality standards, providing the public an opportunity to obtain information and offer their comments on potential ozone nonattainment area boundaries and designations.

On September 2, 2011, the administration announced it would withdraw its proposed 2010 ozone standards.

2008 Eight-Hour Ozone Standard

The 2008 eight-hour ozone standard was published in the Federal Register on March 27, 2008 ( 73 FR 16436 ). An EPA March 2000 memo provided guidance on recommending ozone-area boundaries that are larger or smaller than the Metropolitan Statistical Area, followed by a December 2008 memo. The 2008 standard revised the 1997 eight-hour ozone standard, which was published in the Federal Register on July 18, 1997 ( 62 FR 38856 ). Information about the EPA's ozone standards can be viewed at the EPA's Ozone (O3) Air Quality Standards  webpage. Information from the EPA about eight-hour ozone nonattainment areas can be viewed at the EPA's Green Book 8-Hour Ozone (2008) Area Information webpage.

On January 19, 2010, the EPA published its extension of the deadline for promulgating initial area designations for the 2008 eight-hour ozone standard by one year ( 75 FR 2936 ). The new deadline is March 12, 2011. If the EPA promulgates the proposed 2010 ozone standards, any requirements to designate areas and implement the 2008 eight-hour ozone standard would no longer apply.

On March 10, 2009, the governor submitted a letter to the EPA Region 6 with the state's recommendation covering designations under the federal 2008 eight-hour ozone standard.

Earlier, on December 10, 2008, the commission  approved a nonattainment area designation recommendation. The state's recommendation was due to EPA by March 12, 2009. The commission's recommendation was sent to the governor for consideration.

The TCEQ's Air Quality Division hosted public meetings in July 2008, providing the public an opportunity to obtain information and offer their comments on potential ozone nonattainment boundaries and designations. The division invited written comments to be submitted by September 5, 2008. Copies of the public comments received and a copy of the presentation presented at the meetings are available at the following links:

Monitoring Data

Please visit the Current Ozone Levels webpage to find the current highest ozone levels in each of the metropolitan areas across Texas where ozone is measured by the TCEQ.