Dallas-Fort Worth: Current Attainment Status

DFW Area: Attainment Status by Pollutant

Note: This table is intended to provide a listing of designations and classifications for current, active National Ambient Air Quality Standards (NAAQS). While NAAQS which have been revoked by the EPA do not appear in this table, some anti-backsliding obligations may continue to apply for revoked standards. This table is to be used for informational purposes only and should not be used to determine regulatory requirements in any of the counties listed.

 *The United States Environmental Protection Agency (EPA) revoked the one-hour ozone standard and the 1997 eight-hour ozone standard in all areas, although some areas have continuing obligations under these standards. See ozone history for more information.

**The standard is scheduled to be revoked one year after the effective date of final designations for the 75 ppb standard.

For more information on attainment status, visit the EPA's Green Book webpage regarding nonattainment areas for criteria pollutants.

DFW Nonattainment Areas

2015 Eight-Hour Ozone Standard Designations: Serious Nonattainment, effective July 22, 2024 ( 89 FR 51829 )
On October 1, 2015, the EPA lowered the primary and secondary eight-hour ozone NAAQS to 0.070 parts per million ( 80 FR 65292 ). A nine-county DFW area including Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Tarrant, and Wise Counties was designated nonattainment and classified marginal under the 2015 eight-hour ozone NAAQS, effective August 3, 2018. The DFW nonattainment area includes nine of the ten counties that were designated nonattainment under the 2008 eight-hour ozone but does not include Rockwall County, which was designated attainment/unclassifiable. The attainment date for the DFW marginal nonattainment area was August 3, 2021 with a 2020 attainment year. On October 7, 2022, the EPA reclassified the nine-county DFW area from marginal to moderate nonattainment, effective November 7, 2022 ( 87 FR 60897 ). The attainment date for moderate nonattainment areas was August 3, 2024 with a 2023 attainment year. On June 20, 2024, the EPA reclassified the nine-county DFW area from moderate to serious nonattainment, effective July 22, 2024 ( 89 FR 51829 ). The attainment date for serious nonattainment areas is August 3, 2027 with a 2026 attainment year.

2008 Eight-Hour Ozone Standard Designations: Severe Nonattainment, effective November 7, 2022 ( 87 FR 60926 ) 
On March 27, 2008, the EPA lowered the primary and secondary eight-hour ozone NAAQS to 0.075 parts per million ( 73 FR 16436 ). A 10-county DFW area including Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, Tarrant, and Wise Counties was designated nonattainment and classified moderate under the 2008 eight-hour ozone NAAQS, effective July 20, 2012. On August 23, 2019, the EPA reclassified the 10-county DFW area from moderate to serious nonattainment. The attainment date for serious nonattainment areas was July 20, 2021 with a 2020 attainment year. On October 7, 2022, the EPA reclassified the 10-county DFW area from serious to severe nonattainment. The attainment date for severe nonattainment areas is July 20, 2027 with a 2026 attainment year.

1997 Eight-Hour Ozone Standard Designations: Serious Nonattainment, effective January 19, 2011 ( 75 FR 79302 )  
A nine-county DFW area was originally designated a moderate nonattainment area under the 1997 eight-hour ozone NAAQS and was subsequently reclassified as a serious nonattainment area in 2011. Counties included are Dallas, Denton, Collin, Ellis, Johnson, Kaufman, Parker, Rockwall, and Tarrant.
Status: Based on data from 2012 through 2014, the DFW area monitored attainment of the 1997 eight-hour ozone NAAQS. On February 27, 2015, the TCEQ submitted a request for a finding that the DFW area is attaining the 1997 eight-hour ozone NAAQS. On September 1, 2015, the EPA finalized a clean data determination for the DFW 1997 eight-hour ozone nonattainment area ( 80 FR 52630 ). On November 8, 2016, the EPA published approval of the DFW area redesignation substitute for the one-hour ozone and 1997 eight-hour ozone NAAQS ( 81 FR 78688 ), effective December 8, 2016. On April 5, 2019, the TCEQ submitted a redesignation request and maintenance plan SIP revision to the EPA requesting formal redesignation of the DFW area to attainment for the 1997 eight-hour ozone NAAQS. On April 6, 2020, the EPA published final action on the SIP revision ( 85 FR 19096 ). The final rule terminates all anti-backsliding obligations for the DFW area for the 1997 eight-hour ozone NAAQS and approves the maintenance plan. The action did not redesignate the area to attainment, because the EPA has taken the position that it lacks the authority to redesignate areas to attainment under revoked standards.

2008 Lead Standard Designation: Attainment (Maintenance), effective September 27, 2017 (82 FR 29426 ) 
In the November 22, 2010, Federal Register, the EPA published a determination that an area in Collin County, Texas surrounding Exide Technologies battery recycling plant was not meeting the 2008 lead standard. On August 8, 2012, the commission adopted the Collin County Attainment Demonstration SIP Revision for the 2008 Lead NAAQS and the Agreed Order between Exide and the TCEQ. The Collin County lead nonattainment area was required to attain the 2008 lead standard by December 31, 2015.
Status: The Colin County area achieved compliance of the 2008 lead NAAQS as of December 31, 2015. The TCEQ submitted a SIP revision to request that the EPA redesignate the Frisco lead nonattainment area to attainment based on 36 months of monitoring data below the federal standard.  On June 29, 2017, the EPA published in the Federal Register a direct final rule proposing that the Collin County nonattainment area has attained the 2008 Lead NAAQS and to approve a request that the area be redesignated to attainment, effective September 27, 2017. For additional information, please visit the Dallas-Fort Worth: Lead - Latest Planning Activities webpage.

1978 Lead Standard Designation: Attainment, October 13, 1999 ( 64 FR 55421 ) 
All Texas counties are currently in attainment of the EPA’s 1978 lead standard. Collin County was designated attainment in 1999. A second 10-year maintenance plan for Collin County was adopted by the TCEQ on August 26, 2009, and was approved by the EPA on June 29, 2017 ( 82 FR 29426 ).

National Ambient Air Quality Standards

The EPA has set National Ambient Air Quality Standards (NAAQS) for six principal criteria pollutants: ground-level ozone, lead, carbon monoxide, nitrogen dioxide, sulfur dioxide, and particulate matter.

No later than one year after promulgation of a new or revised NAAQS for any pollutant, the governor must submit designation recommendations to the EPA for all areas of the state. The EPA must then promulgate the designations within two years of promulgation of the revised NAAQS. Areas that do not meet (or contribute to ambient air quality in a nearby area that does not meet) the NAAQS are designated nonattainment. Areas that meet the NAAQS are designated attainment; and areas that cannot be classified based on the available information, unclassifiable.

For ozone, the federal Clean Air Act establishes nonattainment area classifications ranked according to the severity of the area’s air pollution problem. These classifications—marginal, moderate, serious, severe, and extreme—translate to varying requirements with which Texas and nonattainment areas must comply.