On June 9, 2011, U.S. EPA published a notice in the Federal Register making a determination that the St. Louis (MO–IL) metropolitan nonattainment area has attained the 1997 8-hour National Ambient Air Quality Standard (NAAQS) for ozone. The Clean Air Act requires EPA to set NAAQS for wide-spread pollutants from numerous and diverse sources considered harmful to public health and the environm...