OAR 340-202-0100
Ambient Air Quality Standards: Nitrogen Dioxide
(1)
0.053 ppm as an annual average concentration for any calendar year at any site. The standard is met when the annual average concentration in a calendar year is less than or equal to 0.053 ppm, as determined in accordance with appendix S of 40 CFR part 50 for the annual standard.(2)
0.100 ppm as a 3-year average of the annual 98th percentile of the 1-hour daily maximum concentrations recorded at any monitoring site. The standards is met when the three-year average of the annual 98th percentile of the daily maximum 1-hour average concentration is less than or equal to 0.100 ppm, as determined in accordance with appendix S of 40 CFR part 50 for the 1-hour standard.(3)
0.053 ppm as an annual arithmetic mean concentration as determined in accordance with Appendix S of 40 CFR part 50. The secondary standard is attained when the annual arithmetic mean concentration in a calendar year is less than or equal to 0.053 ppm, rounded to three decimal places (fractional parts equal to or greater than 0.0005 ppm must be rounded up). To demonstrate attainment, an annual mean must be based upon hourly data that are at least 75 percent complete or upon data derived from manual methods that are at least 75 percent complete for the scheduled sampling days in each calendar quarter.
Source:
Rule 340-202-0100 — Ambient Air Quality Standards: Nitrogen Dioxide, https://secure.sos.state.or.us/oard/view.action?ruleNumber=340-202-0100.