Illinois Administrative Code
Title 35 - ENVIRONMENTAL PROTECTION
Part 243 - AIR QUALITY STANDARDS
Subpart B - STANDARDS AND MEASUREMENT METHODS
Section 243.123 - Carbon Monoxide

Universal Citation: 35 IL Admin Code ยง 243.123

Current through Register Vol. 48, No. 38, September 20, 2024

a) The 1971 eight-hour and one-hour primary NAAQS for carbon monoxide are as follows:

1) An eight-hour average concentration of 9 ppm (10 mg/m3), not to be exceeded more than once per year; and

2) A one-hour average concentration of 35 ppm (40 mg/m3), not to be exceeded more than once per year.

b) The levels of carbon monoxide in the ambient air must be measured by a method that fulfills either of the following requirements:

1) An FRM based on appendix C of 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) An FEM designated by USEPA and listed in the List of Designated Methods, incorporated by reference in Section 243.108.

c) An eight-hour average concentration must be considered valid if at least 75 percent of the hourly average for the eight-hour period is available. In the event that only six-hour (or seven-hour) averages are available, the eight-hour average must be computed on the basis of the hours available using six (or seven) as the divisor.

d) When summarizing data for comparison with the standards, averages must be stated to one decimal place. Comparison of the data with the levels of the standards in ppm must be made in terms of integers with fractional parts of 0.5 or greater rounded up.

BOARD NOTE: Derived from 40 CFR 50.8.

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