C. Eagar M. Fenn R. Haeuber Thomas G. Huntington S. McLaughlin M. Ross T. Saltman D. Schmeltz M. Streigel C. Trettin R. Cook 2005 <p>Both SO2 and NOx emissions from power generation sources have significantly declined under Title IV. In 2002, SO2 emissions from Title&nbsp;IV-affected sources totaled 10.2 million tons&nbsp;and NOx emissions from all Title IV-affected&nbsp;sources totaled 4.5 million tons, down 35% and&nbsp;33% respectively from 1990 levels. Sources in&nbsp;states with the highest emissions continue to reduce their emissions the most, and there have&nbsp;been no significant geographic shifts in&nbsp;emissions. The benefits of these emission reductions include improvements in air quality&nbsp;(which are expected to lead to significant&nbsp;human health benefits), broad-scale reductions&nbsp;in sulfate deposition, and improvements in visibility. While surface waters in some areas have&nbsp;begun to show signs of recovery from acidification, acidification is still occurring in many&nbsp;areas. Although there have been no broad-scale&nbsp;regional reductions in nitrogen deposition, nitrogen deposition has declined in some areas, benefiting some nitrogen-sensitive forests and coastal&nbsp;waters and acid-sensitive lakes and streams. </p> application/pdf en NOAA Results of the acid rain program: Status and trends of emissions and environmental impacts (1990–2002) chapter