Section 173-476-110 - Ambient air quality standards for PM-2.5(1)Standards for PM-2.5.(a) The three-year average of the annual arithmetic mean concentration of PM-2.5 must not exceed 12.0 [MICRO]g/m3.(b) The three-year average of the ninety-eighth percentile twenty-four-hour average concentration of PM-2.5 must not exceed 35 [MICRO]g/m3.(2)Measurement method. The levels of PM-2.5 in the ambient air must be measured by: (a) A FRM based on 40 C.F.R. Part 50, Appendix L and designated according to 40 C.F.R. Part 53 ; or(b) A FEM designated according to 40 C.F.R. Part 53.(3)Interpretation method. The interpretation method found in 40 C.F.R. Part 50, Appendix N must be used.Wash. Admin. Code § 173-476-110
Adopted by WSR 13-24-010 (Order 12-05), filed 11/21/13, effective 12/22/2013