Background knowledge
Rainwater is always slightly acidic, as carbon dioxide in the air dissolves in rain to form carbonic acid. Acid rain is rain, snow or fog that is polluted by acid in the atmosphere and damages the environment. Two common air pollutants acidify rain: sulphur dioxide (SO2) and nitrogen oxide (NOX). When these substances are released into the atmosphere, they can be carried over long distances by prevailing winds before returning to earth as acidic rain, snow, fog or dust. When the environment cannot neutralize the acid being deposited, damage occurs.<Tab/>…
