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On October 1, 2015, the Environmental Protection Agency (EPA) established the 2015 8-hour ozone National Ambient Air Quality Standard (NAAQS) at a level of 70 parts per billion (ppb), down from the 2008 8-hour ozone NAAQS of 75 ppb. Per the requirements under the Clean Air Act, EPA is required to issue designations of whether counties throughout the United States are meeting the standard (i.e., attainment), not meeting the standard (i.e., nonattainment), or if there is not enough information available to make the determination (i.e., unclassifiable, which is treated as attainment) within two years of revising a NAAQS.

As such, on November 6, 2017, the EPA issued the pre-publication version of the "Final Area Designations for the 2015 National Ambient Air Quality Standards for Ozone (Round 1)." In this pre-publication version, EPA identifies counties that have been determined to be in attainment or unclassifiable for the 2015 ozone NAAQS. Counties that are not listed within this document are not yet considered to be nonattainment areas; however, EPA is extending the time needed to issue designations for those counties not currently listed. EPA plans to address these specific counties in a separate action.

In Texas, there are forty-nine (49) counties that were not included in EPA's pre-publication version of the round 1 determinations for sites classified as attainment or unclassifiable. With only 18 counties currently designated as nonattainment for the 2008 ozone NAAQS, this list has potential for very far-reaching implications with an additional 31 counties being considered for designation as nonattainment. The following counties were not listed in the EPA's list of counties considered to be in attainment or unclassifiable for the 2015 ozone NAAQS:

BexarEl PasoHoodMedinaWalker
Brazoria*Fort Bend*HudspethNavarroWashington
Chambers*Galveston*HuntPalo PintoWharton
CookeGuadalupeKaufman*San Jacinto 

*Currently designated as nonattainment for the 2008 ozone NAAQS.

The majority of the newly listed counties are near the San Antonio area, expansions to the current Dallas Fort-Worth (DFW) nonattainment area, and expansions to the current Houston Galveston Brazoria (HGB) nonattainment area.

Should you own or operate facilities within the counties that are still under consideration of attainment status with the EPA, it is recommended that you pay close attention to the EPA's next steps with regard to the 2015 ozone NAAQS attainment designations. Each site should consider implications for their operations should the county be designated as nonattainment in the future.

Please also note, EPA does allow for comment and filing of petitions for reconsideration of the designations. Considerations of eleven (11) separate factors from the "MEMORANDUM - Boundary Guidance on Air Quality Designations for the 8-Hour Ozone NAAQS" can be used to bolster arguments to assist in documenting why a county should not be classified as nonattainment. Trinity actively assisted sites in evaluating the 11 Factors during the 2008 Ozone NAAQS designation review in Texas, which led to one country remaining attainment that had been recommended as nonattainment by EPA.

Should your facility be located in an area still under consideration for ozone attainment/nonattainment status and you want to discuss potential implications of the pre-publication version of the 2015 ozone NAAQS or how Trinity may be able to assist in reviewing the 11 Factors for your county, please contact the Dallas Office at (972) 661-8100.