A. The primary ambient air quality standards for nitrogen dioxide are:
1. Fifty-three ppb — annual arithmetic mean concentration.
2. One hundred ppb — one-hour average concentration.
B. The secondary ambient air quality standard for nitrogen dioxide is 0.053 ppm (one hundred micrograms per cubic meter), annual arithmetic mean concentration.
C. The primary standards are attained when:
1. The annual arithmetic mean concentration in a calendar year is less than or equal to fifty-three ppb, as determined in accordance with 40 CFR 50, Appendix S.
2. The three-year average of the annual 98th percentile of the daily maximum one-hour average concentration is less than or equal to one hundred ppb, as determined in accordance with 40 CFR 50, Appendix S.
D. The secondary standard is attained when the annual arithmetic mean concentration in a calendar year is less than or equal to 0.053 parts per million, rounded to three decimal places (fractional parts equal to or greater than 0.0005 must be rounded up). To demonstrate attainment, an annual mean shall be based upon hourly data that are at least seventy-five percent complete or upon data derived from manual methods that are at least seventy-five percent complete for the scheduled sampling days in each calendar quarter.
E. The levels of nitrogen dioxide in the ambient air shall be measured by:
1. A reference method based on 40 CFR 50, Appendix F, and designated in accordance with 40 CFR 53; or
2. An equivalent method designated in accordance with 40 CFR 53.
(Ord. 2016-42 § 2 (part), 2016; Ord. 1993-128 § 2 (part), 1993)