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/m^{3}) annual arithmetic mean concentration
and 35 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 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/m^{3}.

(c) The primary 24-hour PM2.5 standard is met when the 98^{th}
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/m^{3}.

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.