The process by which emissions, chiefly sulfur and nitrogen compounds, either react with the atmosphere when deposited on earth by precipitation of snow, rain, or fog with a pH of 5.5 or below, or settle out as acidic particles or gases.
Acidified soils caused toxic aluminum in 66 percent of 565 assessed streams. Diatoms and aquatic macroinvertebrates were moderately to severely affected. These effects have not improved in areas surveyed in the early 1980s
Access to map of data collection sites of the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) with links to other maps and reports on wet atmospheric deposition (chemicals deposited via rain, sleet and snow).
Fact sheet on the formation of acid rain, its effects, investigations, and the program of a nationwide network of acid rain monitoring stations called the National Atmospheric Deposition Program/National Trends Network (NADP/NTN).
Document on the federally supported interagency National Acid Precipitation Assessment Program (NAPAP) covering research on causes and effects of acid precipitation with the USGS as the lead agency for monitoring wet acid deposition.