Section 243.125  8-Hour Ozone

a)         Standard.  The primary and secondary ambient air quality standards for ozone are 0.075  ppm (parts per million) daily maximum 8-hour average concentration, measured and determined in accordance with subsection (b).

b)         Measurement Method.  Ozone shall be measured by a reference method based on 40 CFR 50, appendix D and designated in accordance with 40 CFR 53 (incorporated by reference in Section 243.108) or an equivalent method designated in accordance with 40 CFR 53.  The primary and secondary ambient air quality standards are met when the average of the annual fourth-highest daily maximum 8-hour average ozone concentration is less than or equal to 0.075 ppm, as determined using, 40 CFR 50, appendix P (incorporated by reference in Section 243.108).

(Source:  Amended at 35 Ill. Reg. 18857, effective October 25, 2011)