a paper for background information
In the lower atmosphere, where we live, air is a gas composed of seventy eight percent nitrogen and twenty-one percent of oxygen (by volume). Water vapor is also present. The atmosphere is mixed with argon and carbon dioxide as high as the stratosphere.
Ozone is a gas in the stratosphere that absorbs large amounts of ultraviolet light from the sun, heating the stratosphere and protecting life on earth from solar radiation.
There are other gases which are human-made highly poisonous, like dioxin.
The level of oxygen must be high enough as for every living thing to survive breathing, but it also cannot be so high or it will cause damage to the whole planet, like catching on fire. Every single one those gases, no matter what the smallest amount may be, is important, playing a vital part in the protection of life on earth.
Balance has been the factor keeping all those gases for millions of years. Now man is upsetting such balance thus paying a high price by the problems that he is facing.
The ozone layer is being destroyed. The damage to the ozone layer will take fifty years to return to normal. The loss of ozone is believed to be caused by different chemicals and pollutants that decrease the concentrations that occur naturally in the stratosphere. Skin cancer is one bad consequence, skin rashes headaches, intestinal problems, birth defects; though scientists do not agree on these facts necessarily to be true.
Air pollution is the accumulation in the atmosphere of substances that endanger human health. Some major sources of pollution are burning oil, coal and natural gas which are power and heat generators. Others are the burning of solid wastes, industrial processes and vehicles. Whenever these are burned, waste products are polluting the air.
In Hawaii, measurement of carbon dioxide suggests that it is increasing in the atmosphere at a rate of twenty percent every year. It may alter the earth's climate increasing the average global temperature. The one pollutant that has affected humans more than any other is smog. It is a combination of two words smoke and fog in the air of cities, mostly from burning coal. It was recorded in London, England, of 4000 deaths in a severe fog in 1952. Visibility is affected by smog and it irritates the respiratory system; it contributes to malignancies of many types like eye infections and an increased number of coronary cases have been observed. Very valuable pieces of art are deteriorated while exposed to the environment.
Two other very dangerous gases are carbon dioxide and methane from burned fossil fuels and from rotting vegetation from swamps or from mining. Methane also causes a slow down in the rate at which pollutants act, like sulfur dioxide that causes acid rain.
Meteorological conditions and land forms can influence air pollution concentrations like in cities located in valleys. That atmosphere can carry clouds to where it is then precipitated as acid rain thus causing serious damage to vegetation, waterways and constructions.
Herbicides is one product use to solve certain terrain problems, that has caused worst damage, like the one known as Agent Orange, used in the Vietnam War; now veterans are having health problems . There are also many more forms of air pollution like radioactivity. This one can not be seen or smelled. A very good example is what happened at Chernobyl, an accident at a nuclear power station, in Ukraine, in 1986, an explosion took place and many people were exposed to radioactivity.
Many cities are affected by air pollutants; among them are: Los Angeles, Detroit, Michigan, Chicago, New York, Gary (Indiana), Dallas, Philadelphia, and Birmingham (Alabama).
Air pollution is caused by lots of different pollutants. Cars and trucks are the greatest sources of pollution in USA More than 50% comes from motor vehicles, aircraft, trains, and boats, forest fires, even home's fireplaces. More than 200 million tons of air pollutants are released into the air over U.S. By 1900, air pollution became a serious problem and it has increased as time passes and population increases together with the growth of industrial centers.
In 1960 Congress passed the first law: The Clean Air Act, to help protect our environment. It is intended to reduce air pollution and acid rain. Deadlines to meet clean air standards have been set to control the amount of pollutants that plants can produce.
Also the Environmental Protection Agency helps protect environment. It was established in1970 as it safeguards the environment in the USA It sets policies and standard; and does research. It is a part of the Federal government.
Numerous methods have been proposed for removing pollutants from the atmosphere, but nothing has worked. The only thing that has been practical is controlling at the source of production. So for one, automobiles now are equipped with catalytic devices to decrease emissions of carbon dioxide because for every 25 miles that car runs one pound of pollution is emitted into the air. Filters have been installed at power plants. Still it is not enough. Recycling is a solution for the situation, or the refusal of burying products that are dangerous. Also by reusing some materials.
We also have to be aware of the fact that we live depending on one another. Somehow, we have to consider what there is for us to do about this cause. We have to understand that we damage the atmosphere, the environment where we live, that we depend on it, we are part of it. We must learn and begin to show respect for the world we live in.
Bibliography
Brown, M., The Toxic Cloud: A Cross-Country Report on the Poisoning of America's Air, 1987.
Mackenzie, J.J., Air Pollution's Toll on Forests, 1990.
Nebel, B.J., Environmental Science, 1990.