Parameter Tree:
EARTH SCIENCE > HUMAN DIMENSIONS > ENVIRONMENTAL IMPACTS > ACID DEPOSITION

Definition:
Acid deposition is rain or snow that has a lower pH than precipitation from unpolluted skies. Acid deposition can also include dry forms of deposition such as nitrate and sulfate particles

Reference:
Chiras, Daniel D. 1998. Environmental Science. A Systems Approach to Sustainable Development. Wadsworth Publishing Company. Belmont, California.