Table 7-6: Texas Air Quality Nonattainment Areas for Ozone (O₃)

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KEY: NA = not applicable; U = data are unavailable.

NOTES: Nonattainment areas do not meet the national primary or secondary ambient air quality standard (NAAQS) for the specified pollutant. Nonattainment areas are classified based on design values: Extreme = design value of 0.280 parts per million (ppm) and above; Severe-17 = design value of 0.190 up to 0.280 parts per million (ppm) and has 17 years to reach attainment; Severe-15 = design value of 0.180 up to 0.190 ppm and has 15 years to reach attainment; Serious = design value of 0.160 up to 0.180 ppm; Moderate = design value of 0.138 up to 0.160 ppm; Marginal = design value of 0.121 up to 0.138 ppm; Section 185A = an area designated as an ozone nonattainment area as of the date of enactment of the Clean Air Act Amendments of 1990 and has not violated the national primary ambient air quality standard for ozone for the 36-month period commencing on Jan. 1, 1987, and ending on Dec. 31, 1989.

SOURCE: U.S. Environmental Protection Agency, Green Book, available at http://www.epa.gov/oar/oaqps/greenbk/anay.html as of Apr. 20, 2002.