The D.C. Circuit Court of Appeals has denied petitions for review challenging the decision of the U.S. Environmental Protection Agency (EPA) to designate certain areas of Utah as non-attainment for fine particles (PM2.5) under the Clean Air Act. ATK Launch Sys., Inc. v. EPA, No. 10-1004 (D.C. Cir. 2/24/12).  

Petitioners had asked the court to vacate non-attainment designations of the 2006 daily national ambient air quality standards (NAAQS) for PM2.5 for parts of Tooele and Elder counties near Salt Lake City. They argued that EPA treated those two counties differently when the agency conducted its “nine-factor analysis” and that the analysis was arbitrary and capricious. Those nine factors, which are included in an EPA guidance document, include emission data, air quality data, population density and degree of urbanization, traffic and commuting patterns, growth rates and patterns, meteorology, geography/ topography, jurisdictional boundaries, and level of control of emission sources.  

Characterizing petitioners’ argument as “flawed,” the court ruled, “[b]ecause EPA’s nine-factor test is intended to be applied on a case-by-case basis to account for diverse considerations, including the varying effects of local topography and meteorology on (fine particle) dispersion and EPA reasonably explained its designations, we deny the petitions for review.”