Acid Rain When coal, gasoline, and fuel oils are burned, they contain sulfur, carbon, and nitrogen which goes into the air. These substances, called oxides combine with moisture in the air to form sulfuric acid, carbonic acid, and nitric acid. The pollution may take the form of rain, snow, or fog, or be in dry forms. These acids are brought to Earth in what is called acid rain. The dry form of precipitation is just as damaging to the environment as the liquid form.
During the 20th century, the acidity of the air and acid rain have become a leading threat to the stability and quality of the Earth's environment. Most of this acidity is produced in the industrialized nations of the Northern Hemisphere the United States, Canada, Japan, and most of the countries of Eastern and Western Europe. In 1984 almost half of the trees in Germany's Black Forest had been damaged by acid rain.
The effects of acid rain can be dangerous to many forms of life, including human life. Its effects can be mostly seen, in lakes, rivers, and streams and on vegetation. Acidity in water kills almost all life. By the early 1990s tens of thousands of lakes had been destroyed by acid rain. The problem has been most severe in Norway, Sweden, and Canada.
Winds carry the pollutants around. Some people think that pollution from coal-powered electric generating stations in the midwestern United States is the cause of the severe acid-rain problem in eastern Canada and the northeastern United States. Structures made of stone, metal, and cement have also been damaged or destroyed. Some of the world's great monuments, including the cathedrals of Europe and the Coliseum in Rome, have shown signs of deterioration caused by acid rain.
Scientists use what is called the pH factor to measure the acidity or alkalinity of liquid solutions. On a scale from 0 to 14, the number 0 represents the highest level of acid and 14 the most basic or alkaline. A solution of distilled water containing neither acids or bases, is 7, or neutral. If the pH level of rain falls below 5.5, the rain is considered acidic. Rainfalls in the eastern United States and in Western Europe often range from 4.5 to 4.0.
The cost of antipollution equipment , like burners, filters, and chemical and washing devices is great. But the cost in damage to the environment and human life is much greater because the damage may be irreversible. Preventative measures are being taken. Up to 500,000 lakes in North America and over 4 billion cubic feet of timber in Europe may be destroyed by the end of the 20th Century.
Bibliography Copyright 1992, 1994. Compton's New Media Inc.
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