[20010416]RS20891_空气质量和排放交易：基础.pdf

Congressional Research Service ? The Library of CongressCRS Report for CongressReceived through the CRS WebOrder Code RS20891April 16, 2001Air Quality and Emissions Trading: A PrimerDavid M. BeardenEnvironmental Information AnalystResources, Science, and Industry DivisionSummaryEmissions trading is a market-based mechanism used to lower the costs ofcomplying with air quality regulations. It allows sources facing high pollution controlcosts to meet their emission limits by purchasing excess reductions from other sourcesthat can afford to lower their emissions further than federal or state regulations require.Despite the potential for cost savings, the use of trading has been relatively limited, dueto its suitability for only certain types of pollutants and the complexities ofimplementation and enforcement. Trading is best suited for reducing diffuse pollutantsthat easily spread across broad geographic areas. However, it is not effective inaddressing problems with pollutants that remain locally concentrated because excessreductions made in one location would not improve air quality elsewhere. The extent towhich trading can improve overall air quality also depends on many other factor