Acid Rain

Acid Rain Broadly refers to acidic precipitations—in wet form such as acidic rain, fog, and snow; or in dry form such as acidic gases and particles. Acid rain was first noticed in the late 1960s, when declining fish stocks were observed in Scandinavian lakes, and precipitation was found to be more acidic. Acid rain has also destroyed forests and acidified lakes in Canada as well.

The term acid rain is a misnomer, because even uncontaminated rain has a pH level below 7 and is therefore acidic. The addition of sulphurous and nitrous gases to the atmosphere causes precipitation to become even more acidic as they combine with water. The natural pH of rainwater is about 5.6, but the pH of acidic rain is 4.0–5.0. A decrease ...