One type of air pollution in particular proved to be a serious problem. The burning of coal with a high content of sulfur allowed high levels of sulfur to be dispersed into the atmosphere. This sulfur combines with water vapor in the atmosphere and produces sulfuric acid. Rain and snow carry the sulfuric acid back to earth, often hundreds of miles from where it entered the atmosphere. Rain containing this sulfuric acid is called acid rain.
Acid rain enters lakes and streams and can destroy many forms of life.
It does this by lower the pH level of the water to a level unsuitable for certain forms of life. The acid rain simply makes the water too acidic for many life forms. Scientists first discovered this depletion in 1985, when a hole in the ozone layer was detected over Antarctica. Recently, another hole in the ozone layer has been discovered over the North Pole as well. The depletion of the ozone layer is the result of certain chemicals being released into the atmosphere.