EPA Publishes Proposed Rule on Permits for PM2.5 Emissions

November 16, 2007
Client Alert Newsletter November 2007

To facilitate implementation of the Prevention of Significant Deterioration ("PSD") program for fine particulate matter ("PM2.5") in attainment areas meeting the National Ambient Air Quality Standard ("NAAQS") for PM2.5, the U.S. Environmental Protection Agency ("EPA") proposed, on September 21, calculation options for three key PSD program elements: Increments, Significant Impact Levels ("SILs"), and a Significant Monitoring Concentration ("SMC"). According to the PSD program, when a stationary source applies for a permit to construct or modify a major source in a PM2.5 attainment area, the reviewing authority determines whether the proposed PM2.5 emissions will cause the area to violate the PM2.5 NAAQS or the Increments. In making this determination, the permit reviewing authority will consider, among other things, the PM2.5 Increments, which are allowable concentration increases above the baseline concentration; and the SILs and SMC, which are numerical values that relate to insignificant PM2.5 thresholds. Once finalized, the proposed PM2.5 PSD elements will supplement the final New Source Review ("NSR") implementation rule for PM2.5, and the Increments for coarse particulate matter ("PM10") will no longer have to be used as surrogates under the federal PM2.5 NSR programs. Comments on the proposed rule can be submitted to EPA until January 21, 2008.