Section 096-110-2 - Particulate Matter Ambient Air Quality StandardsA. 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 PM2.5 are: (1) Annual Standards (a) The primary annual PM2.5 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 PM2.5 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 PM2.5 standards are met when the 98th 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/m3.06- 096 C.M.R. ch. 110, § 2