SUBTITLE B: AIR POLLUTION
CHAPTER I: POLLUTION CONTROL BOARD
SUBCHAPTER l: AIR QUALITY STANDARDS AND EPISODES
PART 243 AIR QUALITY STANDARDS
SECTION 243.124 NITROGEN OXIDES (NITROGEN DIOXIDE AS INDICATOR)
Section 243.124 Nitrogen Oxides (Nitrogen Dioxide as Indicator)
a) The level of the 1971 primary annual average NAAQS for nitrogen oxides is 53 ppb, annual average concentration, measured in the ambient air as nitrogen dioxide (NO2).
b) The level of the 2010 primary one-hour NAAQS for nitrogen oxides is 100 ppb, one-hour average concentration, measured in the ambient air as NO2.
c) The level of the 1971 secondary annual average NAAQS for nitrogen oxides is 0.053 ppm (100 µg/m3), annual arithmetic mean concentration, measured in the ambient air as NO2.
d) The levels of the standards in subsections (a) through (c) of this Section must be measured by:
1) An FRM based on appendix F to 40 CFR 50, incorporated by reference in Section 243.108, and designated by USEPA and listed in the List of Designated Methods, incorporated by reference in Section 243.108; or
2) By an FEM designated by USEPA and listed in the List of Designated Methods, incorporated by reference in Section 243.108.
e) The 1971 primary annual average NAAQS for nitrogen oxides in subsection (a) of this Section is met when the annual average concentration in a calendar year is less than or equal to 53 ppb, as determined in accordance with appendix S of 40 CFR 50, incorporated by reference in Section 243.108, for the annual standard.
f) The 2010 one-hour primary NAAQS for nitrogen oxides in subsection (b) of this Section is met when the three-year average of the annual 98th percentile of the daily maximum one-hour average concentration is less than or equal to 100 ppb, as determined in accordance with appendix S of 40 CFR 50, incorporated by reference in Section 243.108, for the 1-hour standard.
g) The 1971 secondary annual average NAAQS for nitrogen oxides in subsection (c) of this Section 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.
BOARD NOTE: Derived from 40 CFR 50.11.
(Source: Amended at 44 Ill. Reg. 14223, effective August 18, 2020)