The sources of air pollution vary. The National Air Pollution Control Administration gives the following percentages :
a. Transportation (cars and buses) : 42.3%
b. Fuel combustion : 21.3%
c. Industrial processes : 13.7%
d. Solid-waste disposal : 5.2%
e. Miscellaneous (agriculture, forest fire) : 17.5%
Many of these sources involve imperfect combustion, a major cause of air contamination. Perfect combustion exists only in the chemistry books and is the result of hydrogen and carbon uniting completely with oxygen, thereby relinquishing heat, water vapor, light, and carbon dioxide to the air. Imperfect combustion refers to the additional liberation of carbon monoxide, sulfur oxides, and nitrogen oxides into the air. Car exhausts in heavy traffic produce a significant amount of carbon monoxide, a colorless and adorless poisonous gas produced during the incomplete combustion of carbon. This gas combines with the hemoglobin of red blood cells in place of oxygen and can produce a hypoxic state, a decreased amount of oxygen in the body. The severity of this state depends on the ratio of carbon monoxide to oxygen in the air inhaled. Guyton states that an alveolar concentration of carbon monoxide of 0.1 percent is lethal. In small amounts, it can cause dizziness, headache, and fatigue. Carbon monoxide pollution can be especially dengerous for persons who suffer from heart disease, respiratory disease, or anemia, for they already have a physiologically impaired oxygen-carrying capacity.
Sulfur oxides are poisonous gases that come from factories and power plants that burn coal or oil-containing sulfur, eventually producing dangerous sulfur dioxide. Sulfur dioxide combines with water to form sulfuric acid (H2SO4), a heavy, corrosive, oily colorness liquid that irritates the sensitive mucous membranes of the eyes, nose, and throat and injures the mucous membrane that lines the lung and the delicate structures accessory to the lung tissue. Besides directly affecting the health of man, sulfur dioxide and its by-product, sulfuric acid, indirectly jeopardize health by damaging plant life and by contributing to rust on metals. In the process of trying to control these harmful effects through technological means, sometimes a new industrial pollution is created. For example, rust-proof cans may contain some elements that contaminate the environment, and they also add to waste-disposal problems.
Other gaseous end products from burning fuels are the nitrogen oxides, especially nitrogen dioxide. While this gas hovers in the air, producing an unpleasant, characteristic odor, it causes irritation to the mucous membranes and creates a haze that destroys the view and blocks out necessary and helpful rays from the sun.
A second type of air contaminant is smog, a noxious mixture of fog and smoke. Smog can be produced when sulfur compounds in smoke react with atmospheric moisture, relinquishing sulfuric acid. Smog can also be produced by hydrocarbons and nitrogen compounds uniting through energy from the sun, forming a type of photochemical smog. Smog often produces a more intense irritation to the mucous membranes than does nitrogen dioxide.
A third type of air contaminant is particulate matter, minute particles such as dust, dirt, air, smoke, and fly ash. Particulate matter, suspended in vapors and fumes, may hover for annoying and dangerous periods of time, depending on atmospheric conditions. These pollutants may soil surfaces, scatter os distribute light rays unevenly, and, most dangerously, enter the lungs of people breathing the air. The severity of the lungs response depends on the precentage of particulate matter or fumes and vapors in the air mixture and on preexisting lung disease. Sufficient exposure to any type of air pollution may lead to pulmonary emphysema (a condition in which the alveoli og the lungs become distended or ruptured). However, cigarette smoking is still the main factor contributing to this serious debilitating condition, according to the U.S. Environmental Protection Agency.
Radioactive substance are produced by mining and processing radioactive ore and by nuclear-fission and radiation procedures used in industry, medicine, and research. Pollution from radioactive materials poses a serious threat to man`s ability ti reproduce and to his gene structure. It is also related to an increase in leukemia, as demonstrated in persons working with radioactive materials over long periods without adequate safeguards and in survivors of Hiroshima and Nagasaki. Over exposure to a radioactive substance requires intensive care-for a person, group, or entire community.
Breathing in asbestos particles released into the atmosphere from certain construction industries and from the wearing of brake lining and cluth facings in cars can cause cancer. Inhaled beryllium, used in making metal alloys, also is known to cause a debilitating form of lung infection. Cigarette smoke has been identified as an air pollutant causing increased carbon monoxide content in the blood, and cardiovascular, respiratory and other symptoms in nonsmokers as well as in smokers.
With all these components circulating in the atmosphere, with harmful radioactive and disease-producing effects from our technology, and with waste in rivers and streams at levels that cannot be detoxified, air pollution exists. All forms of air pollution are physically irritating and present a potential hazard to our long-range health either by direct harm to the muscous membranes of the respiratory tract or by the indirect effects of continuously breathing contaminated air.
A small layer of ozone surrounds the earth and blocks much of the ultraviolet radiation from reaching the earth`s surface. The ozone layer is in danger of being depleted by the continued use of fluorocarbons (Freon) and chlorofluoromethanes which release chlorine into the stratosphere to combine with ozone. The continued use of fluorocarbon-propelled aerosol products and supersonic transport planes would add to that danger. In Caucasians short-wavelength ultraviolet sunlight is thought to cause melanoma and nonmelanoma skin cancer which would increase in incidence if there were a reduction of the ozone layer.
Only as we become aware of these specifics as a personal health threat will we seriously consider alternatives to using two or three cars, seek to know the serious hazards in our jobs, and become concerned about our house downwind from an industrial site or the amount of ultraviolet light we receive.
Ninety percent of air pollution comes from man-made sources and about 70 percent of these emissions are created by the combustion of fossil fuels. The damage to health, property, and vegetation costs the people and the government of the United States approximately $20 billion every year.
There are current signs that the federal government`s air pollution efforts are working because individuals are complying with federal regulations in major industry and the auto industry (emission control systems in cars). Since 1970, sulfur dioxide concentrations have been reduced nationwide by approximately 25 percent. The national average for particulate matter, dust, and smoke has been steadily dropping since 1970. Photochemical oxidants have significantly diminished in those areas where there has been information to identify the trend. Carbon monoxide concentrations in air has dropped 50 percent nationwide. However, only with strict adherence and conscientious efforts will this encouraging tred prevail.
The citizen`s role is a collective role. Consistent public concern to maintain standards and federal regulations must be continued if we are to maintain the execellent effects of existing programs.
References :
League of Women Voters of The United States, Fund Publication No. 393, A Congregation of Vapors. Washington, D.C., 1970.
Guyton, Arthur, Textbook of Medical Physiology. Philadelphia: W. B. Saunders Company, 1966.
Guralnik, David, ed., Webster`s New World Dictionary of the American Language (3nd college ed.). New York: The World Publishing Company, 1972.
Hill, Gladwin, “Clean Air-It`s Up to You too”. Washington, D.C.: Environmental Protection Agency, March, 1973.
Saltonstall, Richard, Your Environment and What You Can Do About It : A Citizens` Guide. New York : Walker and Company, 1970.
Weber, A., C. Jermini, and E. Grandjean, “ Irritating Effects on Man of Air Pollution Due to Cigarette Smoke”, American Jounal of Public Health, 1976.
Fears, Thomas, J. Scott, and M. Schneiderman, “Skin Cancer, Melanoma, and Sunlight”, American Jounal of Public Health, 1976.
Murray, RB and Zentner JP., Nursing Concepts for Health Promotion, Second Edtion, Prentice-Hall, Inc, Englewood Cliffs, N.J, 1979.
