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Summary:
By December 31, 2004, the U.S. Environmental Protection Agency (EPA) intends to finalize the designations of geographical areas for the national ambient (outdoor) air standards for fine particulate matter or ÒPM2.5Ó (particles less than 2.5 micrometers in diameter). Particulate matter, including PM2.5, is one of the six principal pollutants classified as criteria pollutants for which the agency has set National Ambient Air Quality Standards (NAAQS) under the Clean Air Act (CAA). NAAQS are designed primarily to protect human health by providing an adequate margin of safety. After several years of litigation and other delays, EPA is moving to implement the NAAQS for PM2.5 promulgated in 1997.
National PM2.5 air quality data have been collected for three years or more. The next step in the process is the designation of geographical areas for attainment or nonattainment. Areas with air quality levels exceeding the annual and 24-hour PM2.5 standards, which limit the concentration of fine particle levels in the ambient air, will be designated Ònonattainment areas.Ó Many areas that have not been designated as nonattainment under implementation of other NAAQS are expected to be designated nonattainment for the first time with the implementation of the PM2.5 NAAQS.
The designation process is a cooperative federal-state/tribe process in which states/tribes provide initial designation recommendations to EPA for consideration. EPA ultimately makes the decision on the final designations. PM2.5 nonattainment areas will require the development of comprehensive implementation plans to meet the PM2.5 standards.
EPA is currently reviewing the state/tribe attainment designation recommendations, and plans to notify the states/tribes of any modifications by June- July 2004. A preliminary review of the submissions indicates that 18 states and the District of Columbia have recommended 145 counties as potential nonattainment areas. The agency is expected to use its discretion to expand the size and number of nonattainment areas, including designation of additional counties because of their contribution to nonattainment in a defined metropolitan statistical area.
A number of issues will continue to be the topic of debate as the implementation of the PM2.5 NAAQS progresses. Among the questions and concerns are when and why the standards were established; what criteria are used to determine nonattainment; how boundaries of the nonattainment area are established; whether special provisions can be made for areas affected by pollution from upwind; what the deadline will be for reaching attainment; what grants or other funding might be available to assist areas in reaching attainment; and how nonattainment designation might affect economic development and transportation investments in an area.
Actions following the recent release of the 8-hour ozone designations will likely affect certain decisions and the schedule regarding PM2.5 NAAQS implementation. Legislation currently being considered could also potentially alter the implementation process. This report will be updated as developments warrant.
