40 CFR 50.8 - National primary ambient air quality standards for carbon monoxide.

§ 50.8 National primary ambient air quality standards for carbon monoxide.

(a) The national primary ambient air quality standards for carbon monoxide are:

(1) 9 parts per million (10 milligrams per cubic meter) for an 8-hour average concentration not to be exceeded more than once per year and

(2) 35 parts per million (40 milligrams per cubic meter) for a 1-hour average concentration not to be exceeded more than once per year.

(b) The levels of carbon monoxide in the ambient air shall be measured by:

(1) A reference method based on appendix C and designated in accordance with part 53 of this chapter, or

(2) An equivalent method designated in accordance with part 53 of this chapter.

(c) An 8-hour average shall be considered valid if at least 75 percent of the hourly average for the 8-hour period are available. In the event that only six (or seven) hourly averages are available, the 8-hour average shall be computed on the basis of the hours available using six (or seven) as the divisor.

(d) When summarizing data for comparision with the standards, averages shall be stated to one decimal place. Comparison of the data with the levels of the standards in parts per million shall be made in terms of integers with fractional parts of 0.5 or greater rounding up.

[ 50 FR 37501, Sept. 13, 1985]

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United States Code

Title 40 published on 2015-08-22

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 40 CFR Part 50 after this date.

  • 2017-03-28; vol. 82 # 58 - Tuesday, March 28, 2017
    1. 82 FR 15310 - Response to December 9, 2013, Clean Air Act Section 176A Petition From Connecticut, Delaware, Maryland, Massachusetts, New Hampshire, New York, Pennsylvania, Rhode Island and Vermont
      GPO FDSys XML | Text
      ENVIRONMENTAL PROTECTION AGENCY
      Notice of public hearing and extension of comment period.
      Comments. Comments must be received on or before May 15, 2017. Public Hearing. The public hearing will be held on April 13, 2017, in Washington, DC. Please refer to SUPPLEMENTARY INFORMATION section for additional information on the public hearing.
      40 CFR Parts 50 and 51
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