ARM 17.8.211. AMBIENT AIR QUALITY STANDARDS FOR NITROGEN DIOXIDE

(1) No person shall cause or contribute to concentrations of nitrogen dioxide in the ambient air which exceed any of the following standards: (a) hourly average: 0.30 ppm, one-hour average, not to be exceeded more than once per year; (b) annual average: 0.05 ppm, annual average, not to be exceeded. (2) For determining compliance with this rule, nitrogen dioxide shall be measured by the chemiluminescence method, as more fully described in 40 CFR Part 50, Appendix F, incorporated by reference in ARM 17.8.202, or by an approved equivalent method.