This book presents the latest scientific information and analysis concerning the costs, benefits, and environmental effectiveness of the Acid Rain Program (ARP), a bipartisan mandate under Title IV of the 1990 Clean Air Act Amendments signed into law by President George H W Bush to reduce sulphur dioxide (SO2) and nitrogen oxides (NOx) emissions from electric generating sources. Notably, the SO2 program includes the use of a creative emissions cap-and-trade program that combines the best of American science, government, and market-driven innovation. This book focuses on emission reductions from power plants, summarises changes in deposition rates and environmental impacts, and evaluates the ecological effects expected to accompany future reduction in SO2 and NOx emissions.