A reference to water pollution that results when sulfur-bearing minerals associated with coal are exposed to air and water and form sulfuric acid and ferrous sulfate.

The ferrous sulfate can further react to form ferric hydroxide, or "yellowboy", a yellow-orange iron precipitate found in streams and rivers polluted by acid mine drainage.

Also known as "acid precipitation" or "acid deposition", acid rain is precipitation containing harmful amounts of nitric and sulfuric acids formed primarily by sulfur dioxide and nitrogen oxides released into the atmosphere when fossil fuels are burned.

It can be wet precipitation (rain, snow, or fog) or dry precipitation (absorbed gaseous and particulate matter, aerosol particles or dust).

Acid rain has a pH below 5.6. Normal rain has a pH of about 5.6, which is slightly acidic. The term pH is a measure of acidity or alkalinity and ranges from 0 to 14.

A pH measurement of 7 is regarded as neutral. Measurements below 7 indicate increased acidity, while those above indicate increased alkalinity.

Wet acid deposition or the falling of rain (or snow) rich in sulfur and nitrogen oxides.

One of about twenty compounds comprising both a basic amino group and an acidic carboxyl group (organic compound with acidic properties), which combine in their hundreds to form proteins.

A general category that includes batteries with plates made of pure lead, lead-antimony, or lead-calcium immersed in an acid electrolyte.