![]() |
Code of Federal Regulations (Last Updated: July 5, 2024) |
![]() |
Title 40 - Protection of Environment |
![]() |
Chapter I—Environmental Protection Agency |
![]() |
SubChapter C—Air Programs |
![]() |
Part 50 - National Primary and Secondary Ambient Air Quality Standards |
§ 50.20 - National primary ambient air quality standards for PM2.5.
-
§ 50.20 xxx
Link to an amendment published atCross Reference
National primary ambient air quality standards for PM2.5.
(a) The national primary ambient air quality standards for PM2.5 are 9.0 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 to this part, is less than or equal to 9.0 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 to this part, is less than or equal to 35 µg/m3.
[89 FR 16380, Mar. 6, 2024
.]