Designation of Areas for Air Quality Planning Purposes; Deletion of Total Suspended Particulate Designations in Michigan

In this action EPA is deleting Michigan attainment status designations (attainment, unclassifiable and nonattainment) affected by the original national ambient air quality standards (NAAQS) for particulate matter measured as total suspended particulate (TSP). On June 3, 1993 EPA published a final rulemaking action revising the prevention of significant deterioration (PSD) particulate matter increments, so that the increments are measured in terms of particulate matter with an aerodynamic diameter less than 10 microns (PM). Section 107(d)(4)(B) of the Clean Air Act (Act) authorizes EPA to eliminate all area TSP designations once the increments for PM become effective. The June 3, 1993 document, which became effective on June 3, 1994, also established the method by which EPA deletes such TSP designations.