National primary and secondary ambient air quality standards for PM2.5.
(a) The national primary and secondary ambient air quality standards for particulate matter are 15.0 micrograms per cubic meter (µg/m 3) annual arithmetic mean concentration, and 65 µg/m 3 24-hour average concentration measured in the ambient air as PM2.5 (particles with an aerodynamic diameter less than or equal to a nominal 2.5 micrometers) by either:
(1) A reference method based on appendix L of this part and designated in accordance with part 53 of this chapter; or
(b) The annual primary and secondary PM2.5 standards are met when the annual arithmetic mean concentration, as determined in accordance with appendix N of this part, is less than or equal to 15.0 micrograms per cubic meter.
(c) The 24-hour primary and secondary PM2.5 standards are met when the 98 th percentile 24-hour concentration, as determined in accordance with appendix N of this part, is less than or equal to 65 micrograms per cubic meter.
[62 FR 38711, July 18, 1997, as amended at 69 FR 45595, July 30, 2004]
Title 40 published on 2012-07-01
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.
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.