1. A. The eight-hour average primary ambient air quality standard for ozone is 0.070 ppm.
2. B. The eight-hour average secondary ambient air quality standard for ozone is 0.070 ppm.

3. C. To determine attainment of the primary and secondary standards, a person shall measure ozone in the ambient air by:

   1. 1. A reference method based on 40 CFR 50, Appendix D, and designated according to 40 CFR 53; or
   2. 2. An equivalent method designated according to 40 CFR 53.
4. D. The eight-hour average primary ambient air quality standard for ozone is met at an ambient air quality monitoring site when the three-year average of the annual fourth highest daily maximum eight-hour average ozone concentration is less than or equal to 0.070 ppm, determined according to 40 CFR 50, Appendix U.

Historical Note

Amended effective December 22, 1976 (Supp. 76-5). Former Section R9-3-204 repealed, new Section R9-3-204 adopted effective May 14, 1979 (Supp. 79-1). Amended effective October 2, 1979 (Supp. 79-5). Amended effective August 29, 1980 (Supp. 80-4). Amended by deleting subsections (B) through (D) effective September 22, 1983 (Supp. 83-5). Former Section R9-3-204 renumbered without change as Section R18-2-204 (Supp. 87-3). Section R18-2-103 renumbered from R18-2-204 and amended effective September 26, 1990 (Supp. 90-3). Amended by final rulemaking at 11 A.A.R. 3305, effective October 3, 2005 (Supp. 05-3). Amended by final rulemaking at 18 A.A.R. 1542, effective August 7, 2012 (Supp. 12-2). Amended by final rulemaking at 23 A.A.R. 333, effective March 21, 2017 (Supp. 17-1).