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Summary:
Particulate matter (PM), including fine particulate matter (PM2.5), is one of the six principal pollutants for which the U.S. Environmental Protection Agency (EPA) has set National Ambient Air Quality Standards (NAAQS) under the Clean Air Act (CAA). NAAQS are designed to protect human health, with an adequate margin of safety. After years of litigation and other delays, the EPA is moving to implement the NAAQS for PM2.5 promulgated in 1997. Several key implementation milestones are scheduled to be completed during 2007 and 2008. This report provides information on the designation process for PM2.5 "attainment" and "nonattainment" areas and describes the issues that have been raised as the EPA and states develop implementation strategies. The EPA's final designation of 39 areas, consisting of 208 counties in 20 states and the District of Columbia, as nonattainment areas for the 1997 PM2.5 NAAQS became effective April 2005. A combined population of almost 90 million resides in these areas. States with PM2.5 nonattainment areas are required to develop comprehensive implementation plans, referred to as State Implementation Plans (SIPs), demonstrating how attainment will be reached by a designated deadline. SIPs include pollution control measures that rely on models of the impact on air quality of projected emission reductions to demonstrate attainment. States are required to submit SIPs for how they will meet the 1997 PM2.5 NAAQS by April 2008 (three years after the effective date for the final geographic designations), and states must be in compliance by 2010, unless they are granted a five-year extension. The EPA published its final "PM2.5 implementation" rule on April 25, 2007, intended to provide guidance and procedures for establishing controls to achieve and maintain attainment. A number of issues will continue to be debated as the implementation of the 1997 PM2.5 NAAQS progresses. Questions and concerns include the following: what criteria were used to determine nonattainment; whether special provisions can be made for meeting attainment deadlines, particularly for areas affected by upwind pollution; what grants or other funding might be available to help areas reach attainment; and how nonattainment designation might affect economic development and transportation planning in an area. Other EPA recent rulemakings promulgated and proposed that affect various aspects of regulating air quality, in particular the Clean Air Interstate Rule (CAIR) published in May 2005, could influence the PM2.5 NAAQS implementation process. In addition, the EPA's completion of its periodic review of the particulates NAAQS, as required under the CAA, could also affect implementation of the 1997 PM2.5 NAAQS. As part of this CAA review process, on October 17, 2006, the EPA promulgated the final revisions to NAAQS for particulates, both PM2.5 and PM10, that included a strengthening of the 1997 PM2.5 standard. In late December 2006, several states and industry, agriculture, business, and public advocacy groups petitioned the U.S. Court of Appeals for the D.C. Circuit to review the new 2006 particulates NAAQS.
