R18-2-206. Lead

A. The primary ambient air quality standard for lead and its compounds, measured as elemental lead, is 0.15 micrograms per cubic meter – maximum arithmetic mean averaged over a three-month period. B. The secondary ambient air quality standard for lead and its compounds, measured as elemental lead, is 0.15 micrograms per cubic meter – maximum arithmetic mean averaged over a three-month period. C. The level of the standards shall be measured by a reference method based on 40 CFR 50, Appendix G and designated in accordance with 40 CFR 53, or by an equivalent designated in accordance with part 53 of this chapter. D. The national primary and secondary ambient air quality standards for lead are met when the maximum arithmetic three- month mean concentration for a three-year period, as determined in accordance with 40 CFR 50, Appendix R, is less than or equal to 0.15 micrograms per cubic meter. E. The former primary and secondary ambient air quality standards for lead of 1.5 micrograms per cubic meter averaged over a calendar quarter shall apply to an area until one year after the effective date of the designation of that area, pursuant to section 107 of the Act, for the standards in subsections (A) and (B).