The transfer of substances from the air to the surface of the earth, either in wet form (rain, fog, snow, dew, frost, hail) or in dry form (gases, aerosols, particles).
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.
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).