06-096 C.M.R. ch. 110, § 2 - Particulate Matter Ambient Air Quality Standards

A. The primary and secondary 24-hour ambient air quality standards for PM₁₀are 150 µg/m³.The standards are attained when the expected number of days per calendar year with a 24-hour average concentration above 150 um/m³, as determined in accordance with 40 CFR Part 50 Appendix K, is equal to or less than one.

B. The primary and secondary ambient air quality standards for PM_2.5 are:

(1) Annual Standards

(a) The primary annual PM_2.5 standard is met when the annual arithmetic mean concentration averaged over 3 years, as determined in accordance with 40 CFR Part 50 Appendix N, is less than or equal to 12.0 µg/m³.

(b) The secondary annual PM_2.5 standard is met when the annual arithmetic mean concentration averaged over 3 years, as determined in accordance with 40 CFR Part 50 Appendix N, is less than or equal to 15.0 µg/m³.

(2) 24-Hour Standards. The 24-hour primary and secondary PM_2.5 standards are met when the 98^th percentile 24-hour concentration averaged over 3 years, as determined in accordance with 40 CFR Part 50 Appendix N, is less than or equal to 35.0 µg/m³.

Notes

06-096 C.M.R. ch. 110, § 2