Fact About Acid Rain

Facts About Acid Rain

Latest update to this document: 20 February 2003

How Do We Measure Acid Rain?

Acid rain is measured using a scale called "pH", a scale that runs from zero, the most acidic, to 14, the most alkaline. A change of one unit on the pH scale represents a 10-fold change in acidity. Organisms generally thrive near pH 7, the neutral point, and function less successfully toward either end of the scale.

The following diagram shows the pH scale and the pH of some common items:

Pure water has a pH of 7.0. Normal rain is slightly acidic because carbon dioxide dissolves into it, so it has a pH of about 5.5. As of the year 2000, the most acidic rain falling in the US has a pH of about 4.3

Acid Rain Facts

Effects of Acid Rain


The Weather Channel

CS255 Computers in El Ed Home Page

Link to Northern Michigan University

Melissa Boks: mboks@nmu.edu