Code of Federal Regulations Title 40. Protection of Environment § 40.50.18 National primary ambient air quality standards for PM 2.5
Current as of October 02, 2022 | Updated by FindLaw Staff
Welcome to FindLaw's Cases & Codes, a free source of state and federal court opinions, state laws, and the United States Code. For more information about the legal concepts addressed by these cases and statutes, visit FindLaw's Learn About the Law.
(a) The national primary ambient air quality standards for PM2.5 are 12.0 micrograms per cubic meter (μg/m3 ) annual arithmetic mean concentration and 35 μg/m3 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 to this part and designated in accordance with part 53 of this chapter; or
(2) An equivalent method designated in accordance with part 53 of this chapter.
(b) The primary annual PM2.5 standard is met when the annual arithmetic mean concentration, as determined in accordance with appendix N of this part, is less than or equal to 12.0 μg/m3.
(c) The primary 24–hour PM2.5 standard is met when the 98th percentile 24–hour concentration, as determined in accordance with appendix N of this part, is less than or equal to 35 μg/m3.
Cite this article: FindLaw.com - Code of Federal Regulations Title 40. Protection of Environment § 40.50.18 National primary ambient air quality standards for PM 2.5 - last updated October 02, 2022 | https://codes.findlaw.com/cfr/title-40-protection-of-environment/cfr-sect-40-50-18/
FindLaw Codes may not reflect the most recent version of the law in your jurisdiction. Please verify the status of the code you are researching with the state legislature or via Westlaw before relying on it for your legal needs.
Was this helpful?