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WACs > Title 173 > Chapter 173-476 > Section 173-476-110











173-476-100    

173-476-120







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WAC 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 μg/m3.
(b) The three-year average of the ninety-eighth percentile twenty-four-hour average concentration of PM-2.5 must not exceed 35 μg/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.
[Statutory Authority: Chapter 70.94 RCW. WSR 13-24-010 (Order 12-05), § 173-476-110, filed 11/21/13, effective 12/22/13.]