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Acid Rain

Acid Rain


Acid rain forms when sulfur and nitrogen dioxides combine with moisture
in the atmosphere to produce rain, snow, or another kind of precipitation. This
kind of pollution may also be suspended in fog or deposited in a dry form. Acid
rain is most common in North America and Europe. Acid rain has also been
detected in other areas of the world such as tropical rain forests of Africa.
Canada has placed limitations on the sulfur emissions. The United States has
not, so the emissions may still drift into Canada.
The acid rain cycle begins with hundreds of power plants burning
millions of tons of coal. Burning coal produces electricity for us. Coal is
made of carbon, but the coal that we mine is not pure carbon. It is mixed with
other minerals. Two of these are sulfur and nitrogen. Then the coal is burned
some of the sulfur changes into sulfur dioxide and nitrogen changes into
nitrogen oxide. These escape in to the air as poisonous gases. Some smokestacks
release chemicals like mercury, arsenic, and aluminum. Some of these minerals
are changed in to gases and others become tiny specks of ash. As these
chemicals drift, they may change again. They may react with other chemicals in
the air. When sulfur dioxide combines with water, the result is sulfuric acid.
When nitrogen oxide gas combines with water, the result is also another acid.
When the clouds releases rain or other precipitation, the acid goes with it.
This is called acid rain.
The level of acid is measured in pH levels. The pH scale begins at 0
and ends with 14. A reading lower than 7 is called acidic, and a reading higher
than 7 is called basic. Seven is neutral. Normal rain is slightly acidic with a
pH level of about 6.5. Rain with a pH of 5.5 is then times more acidic than
normal rain and rain with pH of 4.5 is a hundred times more acidic than normal
rain. In parts of the country, rain with pH levels of 4.5 to 5.0 is common.
An English scientist named Robert Angus Smith...