Environmental pollution is a term that refers to all the ways that human activity harms the natural environment

Environmental pollution is a term that refers to all the ways that human activity harms the natural environment. Most people have witnessed environmental pollution in the form of an open garbage dump or a factory pouring out black smoke. However, pollution can also be invisible, odorless, and tasteless. Some kinds of pollution do not actually dirty the land, air, or water, but they reduce the quality of life for people and other living things. For example, noise from traffic and machinery can be considered forms of pollution.



Environmental pollution is one of the most serious problems facing humanity and other life forms today. Badly polluted air can harm crops and cause life-threatening illnesses. Some air pollutants have reduced the capacity of the atmosphere to filter out the sun's harmful ultraviolet radiation. Many scientists believe that these and other air pollutants have begun to change climates around the world. Water and soil pollution threaten the ability of farmers to grow enough food. Ocean pollution endangers many marine organisms.



Many people think of air, water, and soil pollution as distinct forms of pollution. However, each of the parts of an environment--air, water, and soil--depends upon the others and upon the plants and animals living within the environment. The relationships among all the living and nonliving things in an environment make up an ecological system, called an ecosystem. All the ecosystems of the earth are connected. Thus, pollution that seems to affect only one part of the environment may also affect other parts. For example, sooty smoke from a power plant might appear to harm only the atmosphere. But rain can wash some harmful chemicals in the smoke out of the sky and onto land or into waterways.



Some pollution comes from one specific point or location, such as a sewage pipe spilling dirty water into a river. Such pollution is called point source pollution. Other pollution comes from large areas. Water can run off farmland and carry pesticides and fertilizers into rivers. Rain water can wash gasoline, oil, and salt from highways and parking lots into the wells that supply drinking water. Pollution that comes from such large areas is called nonpoint source pollution.



Nearly everyone would like to have pollution reduced. Unfortunately, most of the pollution that now threatens the health of our planet comes from products that many people want and need. For example, automobiles provide the convenience of personal transportation, but they create a large percentage of the world's air pollution. Factories make products that people use and enjoy, but industrial processes can also pollute. Pesticides and fertilizers aid in growing large quantities of food, but they also poison the soil and waterways.



To end or greatly decrease pollution, people would have to reduce use of cars and other modern conveniences, and some factories would have to close or change production methods. Because most people's jobs are dependent on industries that contribute to environmental pollution, shutting down these industries would increase unemployment. In addition, if farmers suddenly stopped using chemical fertilizers and pesticides, there would be less food to feed the people of the world.



Over time, however, pollution can be reduced in many ways without seriously disrupting people's lives. For example, governments can pass laws that encourage businesses to adopt less polluting methods of operation. Scientists and engineers can develop products and processes that are cleaner and safer for the environment. And individuals around the world can themselves find ways to reduce environmental pollution.



Types of pollution



The chief types of environmental pollution include air pollution, water pollution, soil pollution, pollution caused by solid waste and hazardous waste, and noise pollution.



Air pollution is the contamination of the air by such substances as fuel exhaust and smoke. It can harm the health of plants and animals and damage buildings and other structures. According to the World Health Organization, about one-fifth of the world's people are exposed to hazardous levels of air pollutants.



The atmosphere normally consists of nitrogen, oxygen, and small amounts of carbon dioxide and other gases and particulates (tiny particles of liquid or solid matter). A number of natural processes work to keep the parts of the atmosphere in balance. For example, plants use carbon dioxide and produce oxygen. Animals, in turn, use up oxygen and produce carbon dioxide through respiration. Forest fires and volcanic eruptions shoot gases and particulates into the atmosphere, and rain and wind wash them out or scatter them.



Air pollution occurs when industries and vehicles release such large amounts of gas and particulates into the air that natural processes can no longer keep the atmosphere in balance. There are two chief types of air pollution: (1) outdoor and (2) indoor.



Outdoor air pollution. Each year, hundreds of millions of tons of gases and particulates pour into the atmosphere. Most of this pollution results from the burning of fuel to power motor vehicles and heat buildings. Some air pollution also comes from business and industrial processes. For example, many dry cleaning plants remove dirt from clothing with a chemical called perchloroethylene, a hazardous air pollutant. The burning of garbage may discharge smoke and heavy metals, such as lead and mercury, into the atmosphere. Most heavy metals are highly poisonous.



One of the most common types of outdoor air pollution is smog. Smog is a brown, hazy mixture of gases and particulates. It develops when certain gases released by the combustion of gasoline and other petroleum products react with sunlight in the atmosphere. This reaction creates hundreds of harmful chemicals that make up smog.



One of the chemicals in smog is a toxic form of oxygen called ozone. Exposure to high concentrations of ozone causes headaches, burning eyes, and irritation of the respiratory tract in many individuals. In some cases, ozone in the lower atmosphere can cause death. Ozone can also damage plant life and even kill trees.



Acid rain is a term for rain and other precipitation that is polluted mainly by sulfuric acid and nitric acid. These acids form when gases called sulfur dioxide and nitrogen oxides react with water vapor in the air. These gases come chiefly from the burning of coal, gas, and oil by cars, factories, and power plants. The acids in acid rain move through the air and water and harm the environment over large areas. Acid rain has killed entire fish populations in a number of lakes. It also damages buildings, bridges, and statues. Scientists believe high concentrations of acid rain can harm forests and soil. Regions affected by acid rain include large parts of eastern North America, Scandinavia, and central Europe.



Chemicals called chlorofluorocarbons (CFC's) are pollutants that destroy the ozone layer in the upper atmosphere. CFC's are used in refrigerators and air conditioners and to make plastic foam insulation. Ozone, the same gas that is a harmful pollutant in smog, forms a protective layer in the upper atmosphere. It shields the earth's surface from more than 95 percent of the sun's ultraviolet radiation. As CFC's thin the ozone layer, more ultraviolet radiation reaches the surface of the earth. Overexposure to such radiation damages plants and greatly increases people's risk of skin cancer.



The greenhouse effect is the warming that results when the earth's atmosphere traps the sun's heat. It is created by carbon dioxide, methane, and other atmospheric gases, which allow sunlight to reach the earth but prevent heat from leaving the atmosphere. These heat-trapping gases are often called greenhouse gases.



Fuel burning and other human activities are increasing the amount of greenhouse gases in the atmosphere. Many scientists believe such an increase is intensifying the greenhouse effect and raising temperatures worldwide. This increase in temperature, called global warming, may cause many problems. A strong greenhouse effect could melt glaciers and polar icecaps, flooding coastal areas. It could also shift rainfall patterns, creating more droughts and severe tropical storms.



Indoor air pollution occurs when buildings with poorly designed ventilation systems trap pollutants inside. The main types of indoor pollutants are tobacco smoke, gases from stoves and furnaces, household chemicals, small fiber particles, and hazardous fumes given off by building materials, including insulation, glue, and paint. In some office buildings, high amounts of these substances cause headaches, eye irritation, and other health problems in workers. Such health problems are sometimes called sick building syndrome.



Radon, a radioactive gas given off through the decay of uranium in rocks within the earth, is another harmful indoor pollutant. It can cause lung cancer if inhaled in large quantities. People can be exposed to radon when the gas leaks into basements of homes built over radioactive soil or rock. Energy-efficient buildings, which keep in heated or cooled air, can trap radon indoors and lead to high concentrations of the gas.



Water pollution is the contamination of water by sewage, toxic chemicals, metals, oils, or other substances. It can affect such surface waters as rivers, lakes, and oceans, as well as the water beneath the earth's surface, called ground water. Water pollution can harm many species of plants and animals. According to the World Health Organization, about 5 million people die every year from drinking polluted water.



In a healthy water system, a cycle of natural processes turns wastes into useful or harmless substances. The cycle begins when organisms called aerobic bacteria use the oxygen dissolved in water to digest wastes. This digestion process releases nitrates, phosphates, and other nutrients (chemical substances that living things need for growth). Algae and aquatic green plants absorb these nutrients. Microscopic animals called zooplankton eat the algae, and fish eat the zooplankton. The fish, in turn, may be eaten by larger fish, birds, or other animals. These larger animals produce body wastes and eventually die. Bacteria break down dead animals and animal wastes, and the cycle begins again.



Water pollution occurs when people put so much waste into a water system that its natural cleansing processes cannot function properly. Some waste, such as oil, industrial acids, or farm pesticides, poisons aquatic plants and animals. Other waste, such as phosphate detergents, chemical fertilizers, and animal manure, pollutes by supplying excess nutrients for aquatic life. This pollution process is called eutrophication. The process begins when large amounts of nutrients flow into a water system. These nutrients stimulate excessive growth of algae. As more algae grow, more also die. Bacteria in the water use up large amounts of oxygen consuming the excess dead algae. The oxygen level of the water then drops, causing many aquatic plants and animals to die.



Water pollution comes from businesses, farms, homes, industries, and other sources. It includes sewage, industrial chemicals, agricultural chemicals, and livestock wastes. Another form of water pollution is the clean but heated water discharged by power plants into waterways. This heated water, called thermal pollution, harms fish and aquatic plants by reducing the amount of oxygen in the water. Chemical and oil spills can also cause devastating water pollution that kills water birds, shellfish, and other wildlife.



Some water pollution occurs when there is improper separation of sewer wastewater from clean drinking water. In parts of the world that lack modern sewage treatment plants, water carrying human waste can flow into drinking water supplies. Disease-carrying bacteria in the waste can then contaminate the drinking water and cause such illnesses as cholera and dysentery. In areas with good sanitation, most human waste flows through underground pipes to special treatment plants that kill the harmful bacteria and remove the solid waste.



Soil pollution is the destruction of the earth's thin layer of healthy, productive soil, where much of our food is grown. Without fertile soil, farmers could not grow enough food to support the world's people.



Healthy soil depends on bacteria, fungi, and small animals to break down wastes in the soil and release nutrients. These nutrients help plants grow. Fertilizers and pesticides can limit the ability of soil organisms to process wastes. As a result, farmers who overuse fertilizers and pesticides can destroy their soil's productivity.



A number of other human activities can also damage soil. The irrigation of soil in dry areas with poor drainage can leave water standing in fields. When this standing water evaporates, it leaves salt deposits behind, making the soil too salty for growing crops. Mining operations and smelters contaminate soil with toxic heavy metals. Many scientists believe acid rain can also reduce soil fertility.



Solid waste is probably the most visible form of pollution. Every year, people dispose of billions of tons of solid garbage. Industrial wastes account for the majority of the discarded material. Solid waste from homes, offices, and stores is called municipal solid waste. It includes paper, plastic, bottles and cans, food scraps, and yard trimmings. Other waste consists of junked automobiles, scrap metal, leftover materials from agricultural processes, and mining wastes known as spoil.



The handling of solid waste is a problem because most disposal methods damage the environment. Open dumps ruin the natural beauty of the land and provide a home for rats and other disease-carrying animals. Both open dumps and landfills (areas of buried wastes) may contain toxins that seep into ground water or flow into streams and lakes. The uncontrolled burning of solid waste creates smoke and other air pollution. Even burning waste in incinerators can release toxic chemicals, ash, and harmful metals into the air.



Hazardous waste is composed of discarded substances that can threaten human health and the environment. A waste is hazardous if it corrodes (wears away) other materials; explodes; ignites easily; reacts strongly with water; or is poisonous. Sources of hazardous waste include industries, hospitals, and laboratories. Such waste can cause immediate injury when people breathe, swallow, or touch it. When buried in the ground or left in open dumps, some hazardous waste can pollute ground water and contaminate food crops.



The mishandling or accidental release of hazardous waste has caused a number of disasters around the world. For example, in 1978, hazardous chemicals leaking from a waste disposal site in the Love Canal area of western New York threatened the health of nearby residents. Hundreds of people were forced to abandon their homes. In 1984, a leak of poisonous gas from a pesticide plant in Bhopal, India, killed more than 2,800 people and caused eye and respiratory damage to more than 20,000.



Some hazardous waste can seriously harm the health of people, wildlife, and plants. These pollutants include radiation, pesticides, and heavy metals.



Radiation is an invisible pollutant that can contaminate any part of the environment. Most radiation comes from natural sources, such as minerals and the sun's rays. Scientists can also produce radioactive elements in their laboratories. Exposure to large amounts of radiation can harm cells and result in cancer.



Radioactive waste produced by nuclear reactors and weapons factories pose a potentially serious environmental problem. Some of this waste will remain radioactive for thousands of years. The safe storage of radioactive waste is both difficult and expensive.



Pesticides can travel great distances through the environment. When sprayed on crops or in gardens, pesticides can be blown by the wind to other areas. They can also flow with rain water into nearby streams or can seep through the soil into ground water. Some pesticides can remain in the environment for many years and pass from one organism to another. For example, when pesticides are present in a stream, small fish and other organisms can absorb them. Larger fish who eat these contaminated organisms build up even larger amounts of pesticides in their flesh.



Heavy metals include mercury and lead. Mining operations, solid waste incinerators, industrial processes, and motor vehicles can all release heavy metals into the environment. Like pesticides, they are long lasting and can spread through the environment. Also, like pesticides, they can collect in the bones and other tissues of animals. In human beings, heavy metals can damage various internal organs, bones, and the nervous system. Many can also cause cancer.



Noise pollution comes from such machines as airplanes, motor vehicles, construction machinery, and industrial equipment. Noise does not dirty the air, water, or land, but it can cause discomfort and hearing loss in human beings and other animals.



Controlling pollution



Controlling pollution depends on the efforts of governments, scientists, business and industry, agriculture, environmental organizations, and individuals.



Government action. In many countries around the world, governments work to help clean up the pollution spoiling the earth's land, air, and water. Such environmental efforts come from both local and national governments. In addition, a number of international efforts have been made to protect the earth's resources.



Local efforts. Many local governments have enacted laws to help clean up the environment. For example, in 1989, California adopted a 20-year plan to reduce air pollution in the Los Angeles area, which had the worst air quality in the United States. The plan includes measures to restrict the use of gasoline-powered vehicles and to encourage the use of mass transportation.



Local governments can also pass recycling laws. Recycling is a process designed to recover and reuse materials instead of throwing them away. In Vienna, Austria, for example, citizens must separate their trash into containers for paper, plastic, metal, aluminum cans, clear glass, colored glass, and food and yard waste. Some cities ban the disposal of yard trimmings in landfills because they take up much space. These cities collect yard trimmings separately and deposit them in compost centers, where the materials decay into a substance used to improve the quality of the soil. Several states in the United States and a number of European countries encourage the reuse of bottles by charging a deposit that is refunded upon return of the bottle.



National efforts. Many national governments also pass legislation to help clean up pollution. In 1980, for example, the U.S. Congress enacted the Comprehensive Environmental Response, Compensation, and Liability Act. This act, also called "Superfund," began a government cleanup of hazardous waste dumps in the United States. This law and others hold polluters responsible for repairing the environmental damage they create.



In the United States, the Environmental Protection Agency (EPA) sets and enforces pollution control standards. It also assists state and local governments in pollution control. Most other industrial countries, including Canada, Japan, and many European countries, also have pollution control agencies.



One of the most effective ways a government can control specific kinds of pollution is by banning the pollutant. In 1972, the U.S. government began a gradual ban on all uses of DDT, a pesticide found to harm wild birds and fish. Unfortunately, some countries still permit use of DDT and other banned pesticides. As a result, imported foods, migratory birds, and even the wind may carry toxic chemicals into the United States.



A government may also ban certain uses of a dangerous substance while permitting others. For example, lead is a poisonous metal that can damage the brain, kidneys, and other organs. The U.S. government bans leaded gasoline and lead-based household paint, but it permits lead in batteries, building materials, and industrial paint. Despite the continued use of lead in some products, restrictions on the metal in paints and gasoline have reduced the health problems it causes.



Still other pollution-control laws limit rather than ban the release of pollutants into the environment. In the United States, the Clean Air Act of 1970 and its amendments have limited the amount of air pollution that cars, power plants, and certain businesses may release. The Clean Water Act of 1972 and its amendments have reduced the discharge of untreated water and harmful chemicals into rivers and other waterways.



Another government strategy to help control pollution is to fine companies for polluting. Australia and a number of European countries fine businesses that pollute waterways. Such fines encourage companies to invest in pollution control equipment or to develop less polluting methods of operation. Governments may also place taxes on products that pollute. For example, most Scandinavian countries tax nonreturnable bottles. Some government regulations simply require businesses to tell the public how many pollutants they release into the environment. This regulation has caused some companies to find ways to reduce pollution so that consumers do not develop an unfavorable impression of them and perhaps refuse to purchase their products.



Governments also regulate the disposal of solid and hazardous wastes. According to U.S. regulations, land-fills must have a double lining of nonporous substances, such as clay and plastic, which helps prevent the escape of toxic chemicals into water supplies. Waste incinerators must have devices that keep harmful gases and particulates from entering the atmosphere.



Global efforts. Many types of environmental pollution have been difficult to control because no single person or nation owns the earth's global resources--that is, its oceans and atmosphere. To control pollution, the people of the world must work together.



Since the 1970's, representatives of many nations have met to discuss ways of limiting the pollution that affects air and water. These nations have created environmental treaties to help control such problems as acid rain, the thinning of the ozone layer, and the dumping of waste into oceans. In a treaty called the Montreal Protocol on Substances That Deplete the Ozone Layer, which took effect in 1989, the major CFC-producing nations agreed to gradually stop producing the chemicals. A 1991 amendment to the treaty called for a total ban on CFC's by 2000. By 1996, most industrialized countries, including the United States, had ended production of CFC's.



In 1992, representatives of 178 nations met in Rio de Janeiro, Brazil, for the United Nations (UN) Conference on Environment and Development. This meeting, known as the Earth Summit, was one of the most important global environmental conferences ever held. The UN members signed agreements on the prevention of global warming, the preservation of forests and endangered species, and other issues.



Scientific efforts. Increasing concern over the environment has caused scientists and engineers to look for technological solutions. Some research seeks ways to clean up or manage pollution. The goal of other research is to prevent pollution. Many industrial researchers are finding more economical ways to use fuels and other raw materials. As a result of their research, some European cities now use waste heat from power plants or trash incinerators to warm homes. New automobile engines burn gasoline much more cleanly and efficiently than older engines. Researchers have also developed automobiles that use such clean-burning fuels as methanol (a type of alcohol) and natural gas. In Brazil, some cars use another type of alcohol, called ethanol, as fuel. Scientists are also developing cars that can use hydrogen gas as fuel. Hydrogen creates almost no pollution when it is burned.



Scientists and engineers are also researching ways to generate electricity more cheaply from such renewable energy sources as the wind and sun, causing little or no pollution. Large fields of windmills, known as wind farms, already supply about 1 percent of California's electricity and more than 2 percent of Denmark's. Devices called photovoltaic cells convert sunlight directly into electricity. Using such cells, a photovoltaic power plant in Sacramento, California, produces enough electricity for 1,000 homes.



Business and industry. Many companies have discovered that it makes good business sense to pollute less. Some have found that reducing pollution gives them a better public image and saves money. Others have developed environmentally safe products or packaging to satisfy consumer demands. Still others develop pollution control systems because they believe that laws will soon force them to do so anyway. And some companies limit pollution because the people running them choose to do so.



In the past, the disposal of wastes was relatively inexpensive for most businesses. Today, legal waste disposal sites have become increasingly scarce and more expensive to use. As a result, many businesses have found ways to produce less waste. For example, manufacturers may use a minimum of packaging and choose packing materials that can be recycled. Lighter packaging means distributors use less fuel transporting the products. In addition, the consumer throws out less packaging and creates less garbage.



Many businesses specialize in different types of pollution management. The business of reducing and cleaning up pollution is expected to be one of the fastest growing industries of the future. For example, some pollution management firms develop devices that remove harmful particulates from smokestack emissions. Particulates can be captured by filters, by traps that use static electricity, or by devices called scrubbers that wash out particulates with chemical sprays.



Other businesses assist companies in following government orders to clean up pollution. Some firms manage recycling or energy conservation programs. Still others help businesses develop less polluting processes.



Regardless of why or how industries begin to clean up pollution, it will be a slow, expensive process. Many businesses rely on the cheapest production methods available, even though such methods pollute. For example, power plants often burn oil and coal to generate electricity because it is generally the most economical method. Manufacturers use cadmium, lead, and mercury in batteries because those metals, though toxic, make batteries work well. When the cost of cleaning up the pollution created by current production methods is added to manufacturing costs, however, less polluting methods may prove more economical.



Agriculture. Scientists and farmers are developing ways to grow food that require less fertilizer and pesticides. Many farmers rotate their crops from year to year to reduce the need for chemical fertilizers. The rotation of corn, wheat, and other crops with legumes, such as alfalfa and soybeans, helps replace nitrogen lost from the soil. Crop rotation also helps control pests and plant diseases. Some farmers use compost and other fertilizers that are less harmful to the soil. Instead of spraying their crops with harmful pesticides, some farmers combat damaging insects by releasing certain other insects or bacteria that prey upon the pests. Scientists are also developing genetically engineered plants that are resistant to certain pests.



The rotation of crops and the use of natural pest enemies are called natural pest control. Combining a limited use of chemical pesticides with natural controls is known as integrated pest management (IPM). Farmers using IPM apply chemical pesticides in smaller amounts and only when they will have the most effect.



Environmental organizations work to help control pollution by trying to influence lawmakers and to elect political leaders who care about the environment. Some groups raise money to buy land and protect it from development. Other groups study the effects of pollution on the environment and develop pollution prevention and management systems. Such groups use their findings to persuade government and industry to prevent or reduce pollution. Environmental organizations also publish magazines and other materials to persuade people to prevent pollution.



Political parties representing environmental concerns have formed in many industrial nations. These organizations, often known as Green parties, have had a growing influence on environmental policies. Countries with Green parties include Australia, Austria, Germany, Finland, France, New Zealand, Spain, and Sweden.



Individual efforts. One of the most important ways an individual can reduce pollution is by conserving energy. Conserving energy reduces the air pollution created by power plants. A reduced demand for oil and coal could also result in fewer oil spills and less destruction of coal-bearing lands. Driving less is one of the best ways to save energy and avoid polluting the air.



People can save electricity by buying more efficient light bulbs and home appliances. For example, compact fluorescent light bulbs use only 25 percent as much electricity as traditional incandescent bulbs. People can also conserve by using appliances less often, by turning off appliances and lights when not in use, and by setting home thermostats at or below 68° F (20° C) in winter and at or above 78° F (26° C) in summer. In addition, buildings with specially treated windows and good insulation need far less fuel or electricity to heat or cool than buildings without such materials.



People can also buy products that are safe for the environment. For example, households can help reduce water pollution by using fewer toxic cleaning products and by properly disposing of any toxic products they do use. If consumers refuse to purchase harmful products, manufacturers will stop making them.



People can also help reduce pollution by eating less meat. Farmers use large quantities of fertilizer and pesticides to raise the grain on which cattle, hogs, and poultry feed. Farmers would use much less fertilizer and pesticides if people chose to eat less meat and more grains, beans, and vegetables. People have also come to expect the perfectly shaped, unmarked fruits and vegetables that most farmers achieve by using large amounts of pesticides. If consumers would accept produce with slight blemishes or imperfections, farmers could reduce their use of chemicals.



One of the simplest ways individuals can prevent pollution is by reusing products. For example, some milk suppliers use glass bottles instead of paper cartons. The bottles may be refilled and used again. People can reuse old paper or plastic bags to carry groceries or to hold garbage. When people reuse products, they avoid both the pollution associated with the creation of a new product and the pollution caused when the product is thrown out.



Recycling is another way of reusing materials. Many cities and towns have recycling programs. Recycling saves energy and raw materials, and it prevents pollution. Many different waste products can be recycled. Commonly recycled wastes include metal cans, glass, paper, plastic containers, and old tires. Cans can be melted down and used to make new ones. Glass can be ground up and made into new containers or used as a substitute for sand in road pavement. Paper can be reprocessed into different paper products. Plastics can be melted down and re-formed into plastic lumber for such uses as fences, decks, benches, and carpeting. Old tires can be burned to produce energy, shredded and added to asphalt, or melted down and molded into such products as floor mats and playground equipment.



The most important way people can fight pollution is to learn as much as possible about how their actions affect the environment. Then they can make intelligent choices that will reduce damage to the planet.



History



Human beings have always caused some environmental pollution. Since prehistoric times, people have created waste. Like garbage today, this waste was either burned, tossed into waterways, buried, or dumped aboveground. However, the waste of early peoples was mostly food scraps and other substances that broke down easily by natural decay processes. Prehistoric populations were also much smaller and were spread out over large areas. As a result, pollution was less concentrated and caused few problems.



The growth of pollution started during ancient times when large numbers of people began living together in cities. As cities grew, pollution grew with them. Poor sanitation practices and contaminated water supplies unleashed massive epidemics in early cities. Environmental problems became even more serious and widespread in the 1700's and early 1800's, during a period called the Industrial Revolution. This period was characterized by the development of factories and the overcrowding of cities with factory workers.



During the Industrial Revolution, coal powered most factories. Most city homes also relied on coal as a heating fuel. The burning of coal filled the air of London and other industrial cities with smoke and soot. Poor sanitation facilities also allowed raw sewage to get into water supplies in some cities. The polluted water caused typhoid fever and other illnesses.



In the United States, air pollution problems became particularly serious in the early 1900's. By the 1930's, smoke and soot from steel mills, power plants, railroads, and heating plants filled the air over many Eastern and Midwestern cities. In some industrial cities, such as Pittsburgh, Pa., and St. Louis, Mo., pollution frequently became so thick that drivers needed streetlights and headlights to see during the day.



Progress in controlling pollution has gained speed since the 1960's. Nearly all the railroads, industries, and homes of western Europe and the United States have switched from coal to cleaner-burning fuels, such as oil and natural gas. In many other places, pollution controls effectively limit the air pollution created by coal burning. Today, cities in many parts of the world also treat their water and process their sewage, thus greatly reducing the problems caused by harmful bacteria.



Important progress has been made in other areas of pollution management. Industrial waste, sewage, fertilizers, and other contaminants have polluted the Great Lakes since the mid-1800's. By the early 1970's, Lake Erie, Lake Ontario, and shallow regions of Lake Huron and Lake Michigan were so polluted that the waters had turned green and smelled foul, and huge fish kills were common. In 1972, Canada and the United States signed the Great Lakes Water Quality Agreement. Since then, local governments around the lakes have improved sewage treatment plants, controlled the runoff of chemical fertilizers from farms, and worked to reduce the use of phosphate detergents. They have also forced industries to reduce the pollutants they dump into the lakes. Today, the Great Lakes are much cleaner.



Current environmental issues



Current environmental issues include the need to weigh the benefits and risks of pollution controls, and the effects of population growth.



Weighing benefits and risks. Increased concern about the environment has caused people to protest many products and practices. Some of the disputed products and processes provide benefits to society. For example, people have argued against the use of disposable diapers because they take up space in landfills and decay slowly. But cloth diapers must be washed, and washing pollutes water and consumes energy. Nuclear power plants generate energy without creating air pollution. But such plants produce radioactive waste, which is difficult to dispose of. Business, environmental groups, and scientists work to determine which products, materials, and processes produce the most pollution. However, few choices are clear cut. It is often difficult to determine the relative risks and benefits to the environment of various products and practices.



When creating pollution laws, government officials must consider both the dangers of the pollutant and the possible financial effects of regulation. Regulations often require that an industry purchase expensive pollution control devices, make costly production changes, or discontinue manufacturing certain products. Such sudden expenses can cause some industries to go out of business, which creates unemployment. As a result, the effects of certain proposed pollution laws could harm people more than the pollutant would.



Effect of population growth. Despite progress in protecting the environment, the problem of pollution has become increasingly widespread and potentially more harmful. The main cause for the increase in pollution is that the earth's population grows larger every day. More people means more waste of every kind. As a result, one of the most important ways to begin controlling environmental pollution is to slow population growth. A reduction in population growth would slow the destruction and give people more time to develop effective pollution control systems.



Most of the world's population growth occurs in the poorest parts of the world, including certain nations in Africa, Asia, and Latin America. In these areas, people use what little resources they have just trying to keep alive. Governments in developing countries struggle to build modern industries and agricultural systems to provide a basic standard of living for their citizens. However, many developing countries use old technology that tends to pollute because they cannot afford modern, efficient machinery. Even if they could afford pollution controls, pollution in the developing world would continue to rise simply because these nations are industrializing. And more industry means more pollution.



Wastefulness in the industrialized world. Many people in Japan and wealthier nations in North America and Europe have become accustomed to comfortable lifestyles that consume large amounts of energy and raw materials and produce many wastes. A person living in an industrialized nation uses about 10 times the amount of fossil fuels and electricity and produces 2 to 3 times as much municipal waste as a person in a developing country. For a true reduction in pollution, people in the industrialized world would probably have to accept less convenience and luxury in their lives. Solving the problems of global environmental pollution will require the cooperation of governments and industry in all countries, rich and poor, as well as the efforts of individuals all over the world.



Contributor: Marian R. Chertow, M.P.P.M., Director, Partnership for Environmental Management, Yale School of Forestry and Environmental Studies.



Questions



How can consumers encourage manufacturers to produce less polluting products?



What causes most air pollution?



What natural processes cleanse water systems?



How does the desire for convenience contribute to environmental pollution?



What are some ways governments work to control pollution?



Why is solid waste difficult to eliminate?



How does population growth contribute to environmental pollution?



What are the hazards and benefits of ozone in the atmosphere?



How can businesses help reduce pollution?







Additional resources



Level I



Markle, Sandra. The Kids' Earth Handbook. Atheneum, 1991.



Stefoff, Rebecca. The American Environmental Movement. Facts on File, 1995.



Level II



Baer-Brown, Leslie, and Rhein, Bob. Earth Keepers: A Sourcebook for Environmental Issues and Action. Mercury Hse., 1995.



Eblen, Ruth A. and W. R., eds. The Encyclopedia of the Environment. Houghton, 1994.



Harte, John, and others. Toxics A to Z. Univ. of Calif. Pr., 1991.