40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

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§ 50.17 National primary ambient air quality standards for sulfur oxides (sulfur dioxide).
(a) The level of the national primary 1-hour annual ambient air quality standard for oxides of sulfur is 75 parts per billion (ppb, which is 1 part in 1,000,000,000), measured in the ambient air as sulfur dioxide (SO2).
(b) The 1-hour primary standard is met at an ambient air quality monitoring site when the three-year average of the annual (99th percentile) of the daily maximum 1-hour average concentrations is less than or equal to 75 ppb, as determined in accordance with appendix T of this part.
(c) The level of the standard shall be measured by a reference method based on appendix A or A-1 of this part, or by a Federal Equivalent Method (FEM) designated in accordance with part 53 of this chapter.
[75 FR 35592, June 22, 2010]

Title 40 published on 2014-07-01

no entries appear in the Federal Register after this date.

This is a list of United States Code sections, Statutes at Large, Public Laws, and Presidential Documents, which provide rulemaking authority for this CFR Part.

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United States Code

Title 40 published on 2014-07-01

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

  • 2015-01-05; vol. 80 # 2 - Monday, January 5, 2015
    1. 80 FR 278 - National Ambient Air Quality Standards for Lead
      GPO FDSys XML | Text
      Proposed rule.
      Comments must be received on or before April 6, 2015. Public Hearings: If, by January 26, 2015, the EPA receives a request from a member of the public to speak at a public hearing concerning the proposed decision, we will hold a public hearing, with information about the hearing provided in a subsequent notice in the Federal Register .
      40 CFR Part 50