Draft Technical Support Document MISSOURI Area Designations For the 2010 SO 2 Primary National Ambient Air Quality Standard

Summary Pursuant to section 107(d) of the Clean Air Act (CAA), EPA must initially designate areas as either “unclassifiable”, “attainment”, or “nonattainment” for the 2010 1-hour sulfur dioxide (SO 2) primary national ambient air quality standard (NAAQS). The CAA defines a nonattainment area as one that does not meet the NAAQS or that contributes to poor air quality in a nearby area that does not meet the NAAQS. Table 1 below identifies the counties or portions of counties (or Indian Country) in Missouri that EPA intends to initially designate “nonattainment” based on monitored violations.