The USEPA intends to designate the entire state of Iowa as "unclassifiable/attainment" for the proposed annual PM2.5 NAAQS standard of 12 ug/m3 (previously 15 ug/m3). The USEPA made this determination based on 2011-2013 air quality data and information provided by the state of Iowa. A 30-day public comment period will begin soon to allow for comments on this preliminary decision. USEPA anticipates promulgating the final annual PM2.5 designations in December 2014.