(1) No person may cause or contribute to concentrations of PM-10 in the ambient air which exceed the following standards:

(a) Twenty-four hour average: 150 µg/m³ of air, 24-hour average, with no more than one expected exceedance per calendar year.

(b) Annual average: 50 µg/m³ of air, expected annual average, not to be exceeded.

(2) For the purposes of this rule, expected exceedance and expected annual average shall be determined in accordance with 40 CFR Part 50, Appendix K, incorporated by reference in ARM 17.8.202.

(3) For determining compliance with this rule, PM-10 shall be measured by an applicable reference method based on 40 CFR Part 50, Appendix J, and designated in accordance with 40 CFR Part 53 or by an equivalent method designated in accordance with 40 CFR Part 53, all incorporated by reference in ARM 17.8.202.