WAC 173-476-100. Ambient air quality standard for PM-10

(1) Standard for PM-10. The twenty-four-hour average concentration of PM-10 in the ambient air must not exceed 150 µ g/m 3 more than one time per year, on a three-year average. (2) Measurement method. The levels of PM-10 in the ambient air must be measured by: (a) A FRM based on 40 C.F.R. Part 50, Appendix J 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 K must be used.