Acid precipitation is any form of precipitation, including rain, snow, hail, fog, or dew that is high in acid pollutants, especially sulfuric and nitric acid. It is precipitation with higher than normal amounts of Nitric and Sulphuric acid causing a lower PH Level. These higher amounts of acid are due to anthropomorphic systems.

The pH scale is used to measure how basic or acidic a liquid is. The pH scale ranges from 0 to 14. Bases are from 7 to 14 and acids are found between 0 and 7. The lower the number on the scale the more acidic the liquid is and the higher the number on the scale the more basic the liquid is.