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Pollution in Its Many Forms
One of the most serious problems facing the world today is pollution,
that is the contamination of air, land and water by all kinds of
chemicals such as poisonous gases, waste materials and insecticides.
Pollution has upset the balance of nature, destroyed many forms of
wildlife and caused a variety of illnesses. It occurs in every country on
Earth but is most prominent in industrial countries.
Breathing polluted air is very common to most people, especially
those living in cities. In heavily industrialized areas, fumes from car
exhausts and thick smoke from factory chimneys can be seen
darkening the atmosphere. This would reduce visibility and make the
air unpleasant to breathe. Large scale burning of fossil fuels, such as
coal, gas and oil, in homes and industries also produces a wide range
of pollutants. This includes sulfur dioxide which damages plants,
destroys buildings and affects health. Other known pollutants are
carbon monoxide, nitrogen dioxide and dirt particles. The fumes
produced by car exhausts and factories would normally disperse in
the air, but sometimes they are trapped by air layers of different
temperatures. The result is a fog-like haze known as smog. Britain
and some other countries introduced smokeless zones and smokeless
fuels some years ago and smog no longer occurs, but it still remains a
very real problem in Japan and the United States.
The motor car is a major source of pollution. In densely populated
cities where there are millions of cars on the roads, the level of
carbon monoxide in the air is dangerously high. On windless days,
the fumes settle near ground level. Fumes from car exhausts also
pour out lead and nitrogen oxide.
The testing of nuclear weapons, and the use of atomic energy for
experimental purposes in peaceful times have exposed some people
to levels of radiation that are too high for safety. Crop-spraying by
aircraft also adds chemical poisons to the air.
Domestic rubbish is another very serious pollution problem. The
average American citizen throws away nearly one ton of rubbish every year.
Much of this consists of plastic, metal and glass packaging that cannot be
broken down naturally. Instead it lies with old refrigerators, broken washing
machines and abandoned cars in huge piles for years without decaying. Each
year the problem of rubbish disposal becomes more serious.
Sewage causes another form of pollution. Most of it flows straight into
rivers, where it is broken down by tiny bacteria. The bacteria need oxygen for
this process, but because of the vast quantities of sewage, the bacteria
uses up
all available oxygen in the water, causing the death of countless fish and other
river life. Rivers provide a very convenient outlet for industrial waste, as well
as being a source of water for cooling in nuclear and other power plants.
Like rivers, oceans have been used as dumping grounds for waste of all
kinds. One of the recent sources of sea pollution is oil and millions of tons of
it spill into the sea each year. Oil not only pollutes beaches, it also kills fish and
seabirds. |
