15A NCAC 02D .0410 PM2.5 PARTICULATE MATTER
(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 40 C.F.R. Part 50 and designated in accordance with 40 C.F.R. Part 53; or
(2) An equivalent method designated in accordance with 40 C.F.R. Part 53.
(b) The primary annual PM2.5 standard is met when the annual arithmetic mean concentration, as determined in accordance with appendix N of 40 C.F.R. Part 50, 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 40 C.F.R. Part 50, is less than or equal to 35 µg/m3.
History Note: Authority G.S. 143-215.3(a)(1); 143-215.107(a)(3);
Eff. April 1, 1999;
Amended Eff. September 1, 2015; January 1, 2010.