Section 401 - SUSPENDED PARTICULATE STANDARDS (PM[10])401.1 The concentration in the ambient air of particulate matter with an aerodynamic diameter of less than ten (10) micrometers (PM10) shall not exceed: 401.11 One hundred and fifty (150) micrograms per cubic meter of air as a 24 hour average more than once a year.401.12 Fifty (50) micrograms per cubic meter of air as an annual arithmetic mean.401.2 Sampling and analysis for suspended particulates shall be conducted according to the method outlined in Section 180. Wash. Admin. Code Northwest Clean Air Agency, 400, 401
AMENDED: October 13, 1982, April 14, 1993