Nos. 09-10249, 09-10258. Argued and Submitted June 15, 2010. Filed September 20, 2010. Milagros A. Cisneros, Assistant Federal Public Defender, Phoenix, AZ, for the defendants-appellants. Joan G. Ruffennach, Assistant U.S. Attorney, Phoenix, AZ, for the plaintiff-appellee. Appeal from the United States District Court for the District of Arizona, David G. Campbell, District Judge, Presiding. D.C. Nos. 3:08-cr-01203-DGC-1, 3:08-CR-01202-DGC-1. Before: MARY M. SCHROEDER and JAY S. BYBEE, Circuit Judges
(a) The level of the national 8-hour primary and secondary ambient air quality standards for ozone (O3) is 0.075 parts per million (ppm), daily maximum 8-hour average, measured by a reference method based on appendix D to this part and designated in accordance with part 53 of this chapter or an equivalent method designated in accordance with part 53 of this chapter. (b) The 8-hour primary and secondary O3 ambient air quality standards are met at an ambient air quality monitoring site when the 3-year