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On April 30, 2018, this rule established initial air quality designations for all the remaining areas in USA, except for 8 counties in San Antonio, Texas area. Those areas will be designated by July 17, 2018. These final designations will take effect 60 days after the notice is published in the Federal Register. Areas are being designated as either:

  • Nonattainment: not meeting the standards
  • Attainment/ unclassifiable: meeting the standard and not contributing to a violation of the standard
  • Unclassifiable: available monitoring data is not sufficient to make a determination (1 area)

Areas designated as nonattainment are also being classified by severity of their air quality problems as Marginal, Moderate, Serious, Severe, or Extreme. Below is a table that provides details for each of the counties designated as nonattainment in Texas.

2018.05 TX eNews-Website Article Table 1


The Clean Air Act requires air agencies to control ozone pollution in nonattainment areas by making stricter controls on industrial facilities. State implementation plans (SIPs) are made to assist in meeting of ozone standards. For all non-attainment areas, states have 3-4 years to develop and submit SIPs depending on classification. Nonattainment areas are required to meet the standard as quickly as possible, but the maximum time from the effective date of designation for each classification is:

2018.05 TX eNews-Website Article Figure 1


Nonattainment areas with a "lower" classification have ozone levels that are closer to the standard than areas with a "higher" classification. Areas in the lower classification levels have fewer and/or less stringent mandatory air quality planning and control requirements than those in higher classifications.  Below is a table of each nonattainment area's design value, based on the most recent 3 years of certified air quality monitoring data. EPA must determine whether the area has attained the standard by the applicable attainment date. If an area fails to meet the standard, a new SIP must be submitted to demonstrate attainment by the attainment date for the new classification.

2018.05 TX eNews-Website Article Table 2


For more information, please refer to EPA's Additional Air Quality Designations for the 2015 Ozone National Ambient Air Quality Standards for more information or contact the Trinity office nearest you by calling (800) 229-6655 for more information.