Determination of attainment. EPA has determined, as of May 23, 2011, that the St. Louis (MO-IL) metropolitan 1997 PM2.5 nonattainment area has attained the 1997 PM2.5 NAAQS. This determination, in accordance with 40 CFR 51.1004(c), suspends the requirements for this area to submit an attainment demonstration, associated reasonably available control measures, reasonable further progress, contingency measures, and other plan elements related to attainment of the standards for as long as the area continues to meet the 1997 PM2.5 NAAQS. In addition, based upon EPA's review of the air quality data for the 3-year period 2007 to 2009, the St. Louis (MO-IL) PM2.5 nonattainment area has attained the 1997 PM2.5 NAAQS by the applicable attainment date of April 5, 2010. [77 FR 38185, June 27, 2012]