Approval and Promulgation of Air Quality Implementation Plans; Michigan; Determination of Attainment of the 1997 Annual Fine Particle Standard for the Detroit-Ann Arbor Nonattainment Area

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EPA is making two final determinations under the Clean Air Act (Act) regarding the 1997 annual fine particle (PM 2.5 ) nonattainment area of Detroit-Ann Arbor, Michigan (Livingston, Macomb, Monroe, Oakland, St. Clair, Washtenaw, and Wayne Counties) (Detroit-Ann Arbor area or area). First, EPA is determining that the Detroit-Ann Arbor area has attained the 1997 annual PM 2.5 National Ambient Air Quality Standard (NAAQS). EPA made this determination of attainment based upon complete, quality-assured, and certified ambient air monitoring data for 2009-2011, showing that the area has monitored attainment of the 1997 annual PM 2.5 NAAQS. Preliminary data available for 2012 indicate continued attainment. Pursuant to EPA rule, this determination suspends the requirements for the Detroit-Ann Arbor area to submit an attainment demonstration, associated reasonably available control measures (RACM) to include reasonably available control technology (RACT), a reasonable further progress (RFP) plan, contingency measures, and other planning State Implementation Plan (SIP) revisions related to attainment of the 1997 annual PM 2.5 NAAQS so long as the area continues to attain the PM 2.5 NAAQS. EPA