A. The primary ambient air quality standard for sulfur oxides measured as sulfur dioxide using the reference method described in 40 CFR 50, Appendix A or A-1, or by an equivalent method, is:
1. Seventy-five parts per billion (ppb) — maximum one-hour concentration. The one-hour primary standard is met at an ambient air quality monitoring site when the three-year average of the annual 99th percentile of the daily maximum one-hour average concentration is less than or equal to seventy-five parts per billion, as determined according to 40 CFR 50, Appendix T.
B. The secondary ambient air quality standard for sulfur oxides, measured as sulfur dioxide is 0.5 parts per million (ppm) (1300ìg/m 3 )—maximum 3-hour concentration not to be exceeded more than once per year.
(Ord. 2016-42 § 2 (part), 2016; Ord. 2005-93 § 1 (part), 2005; Ord. 1993-128 § 2 (part), 1993)