40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator).

Status message

There is 1 rule appearing in the Federal Register for 40 CFR 50. View below or at eCFR (GPOAccess)
§ 50.11 National primary and secondary ambient air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator).
(a) The level of the national primary annual ambient air quality standard for oxides of nitrogen is 53 parts per billion (ppb, which is 1 part in 1,000,000,000), annual average concentration, measured in the ambient air as nitrogen dioxide.
(b) The level of the national primary 1-hour ambient air quality standard for oxides of nitrogen is 100 ppb, 1-hour average concentration, measured in the ambient air as nitrogen dioxide.
(c) The level of the national secondary ambient air quality standard for nitrogen dioxide is 0.053 parts per million (100 micrograms per cubic meter), annual arithmetic mean concentration.
(d) The levels of the standards shall be measured by:
(1) A reference method based on appendix F to this part; or
(2) By a Federal equivalent method (FEM) designated in accordance with part 53 of this chapter.
(e) The annual primary standard 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 this part for the annual standard.
(f) The 1-hour primary standard 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 100 ppb, as determined in accordance with appendix S of this part for the 1-hour standard.
(g) 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.
[75 FR 6531, Feb. 9, 2010]

Title 40 published on 2013-07-01

The following are only the Rules published in the Federal Register after the published date of Title 40.

For a complete list of all Rules, Proposed Rules, and Notices view the Rulemaking tab.

  • 2013-07-03; vol. 78 # 128 - Wednesday, July 3, 2013
    1. 78 FR 40000 - Method for the Determination of Lead in Total Suspended Particulate Matter
      GPO FDSys XML | Text
      ENVIRONMENTAL PROTECTION AGENCY
      Final rule.
      This final rule is effective on August 2, 2013.
      40 CFR Part 50

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.

This list is taken from the Parallel Table of Authorities and Rules provided by GPO [Government Printing Office].

It is not guaranteed to be accurate or up-to-date, though we do refresh the database weekly. More limitations on accuracy are described at the GPO site.


United States Code

Title 40 published on 2013-07-01

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

  • 2014-02-13; vol. 79 # 30 - Thursday, February 13, 2014
    1. 79 FR 8644 - Notice of Workshop in Support of the Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Sulfur
      GPO FDSys XML | Text
      ENVIRONMENTAL PROTECTION AGENCY
      Notice of workshop.
      The workshop will be held March 4-6, 2014. The pre-registration deadline is February 28, 2014.
      40 CFR Part 50