HOW DOES POLLUTION AFFECT OUR WORLD?

Transcription

1 The Killer Smogs HOW DOES POLLUTION AFFECT OUR WORLD? On the night of December 1, 1930, a dense fog moved over the Meuse Valley, in Belgium. Many factories in the valley poured smoke and fumes into the foggy air. This created a dark smog of smoke and fog combined. People in the valley began to cough and strain for breath. The smog remained for four days. During that time, thousands or people became ill. The hospitals were filled with patients. Sixty people died. Most of them were older persons with heart and lung problems. Finally, a heavy rain washed away the smog. Scientists studied the causes of the disaster. They concluded that illnesses and deaths were caused by chemicals in the smog. The first reported event of this kind in the United States happened in Donora, a factory town in a valley near Pittsburgh. In 1948, a killer smog made half of the population sick; there were 17 deaths. Again, older people with lung or heart ailments were hit hardest. London, England, has always been known for its "black fogs". In the winter of 1952, a milky white fog rolled into the city. It soon turned into black smog as the smoke of the city poured into the air. It was so hard to see that people had to walk in front of the buses to guide them. In this way, the most serious air pollution disaster in history began. When it was over, more than 4,000 people had been killed by the thick black smog. New York City has had several London-type smogs since Each time, there were from 100 to 400 deaths caused by the smog. Although these smogs were not as deadly as London's, New York City has the worst air pollution problem in the United States. What Is Smog? In all the killer smogs, factories and homes poured smoke and fumes into the air from the furnaces. The chemical fumes combined with the water droplets in the fog to form harmful substances. These substances caused the illness of those who breathed the polluted air. Usually, such harmful fumes rise into the upper air and are blown away by the wind. But sometimes there is an unusual weather condition called a temperature inversion. A layer of cold air remains near the ground as smoke and fumes pour into it. This is covered by an upper layer of warm air that acts like a lid. It prevents the polluted cooler air from rising. The harmful fumes pile up and make people ill. These fumes contain sulphur dioxide, soot particles, and other chemicals. The smog may be so thick that airports are closed and chains of collision occur on the highways. Another type of smog occurs in Los Angeles. Here the weather may be clear and sunny. But stinging eyes and dry coughs show that harmful chemicals fill the air. The smog is due to invisible gases, mostly from automobile exhausts. Because these chemicals are changed by the sun high up in the air, Los Angeles smog is called photochemical smog. It contains automobile exhaust fumes and nitrogen oxides altered by the sun's rays. Added to these are sulphur dioxide and other fumes from factories and oil refineries. Photochemical smog is found in many large cities all over the world. Chemicals that Pollute the Air Killer smogs do not happen very often, fortunately, but in many large cities a combination of automobile exhaust fumes, home furnace smoke, and factory waste gases pours into the air. This may also happen in the suburbs, or out in the country, where large factories have been

2 built. A number of harmful substances have been found in the air there. When these substances are breathed in day after day, the health of the population is affected. Sulphur dioxide is formed when fuels containing sulphur are burned. The sulphur combines with the oxygen in the air to form sulphur dioxide. This gas probably caused most of the deaths in the killer smogs. It combines with water droplets in the air, or with the mucus in the respiratory system. This can form sulphuric acid. Experiments with animals show that sulphur dioxide can paralyze or destroy the cilia in the air passages. It damages the lungs and lowers the resistance to pneumonia and influenz It can also cause bronchitis and emphysem Soot is the black or gray smoke which comes from chimneys and smoke stacks. It consists of particles that float in the air and then settle on the ground. Cancer-producing chemicals have been found in soot. They are suspected of causing lung cancer. It is well-known that populations living where there is severe air pollution have a higher rate of lung cancer than people who live where there is clean air. However, most cases of lung cancer are probably caused by smoking cigarettes. Carbon monoxide is produced by all automobile engines. Defective furnaces can also produce this gas. When carbon monoxide enters the lungs it combines with the haemoglobin of the red blood cells. This prevents the red blood cells from carrying oxygen all round the body. Where there are traffic jams, carbon monoxide may pile up in the air. It can cause headaches and dizziness. Sometimes carbon monoxide can enter the body of a car because of a leak in the exhaust system. In such cases it can cause serious illness or even death. Nitrogen oxides are produced in an automobile engine when the nitrogen and the oxygen of the air are combined. This happens because of the great heat of the engine. Nitrogen oxide gases rise in the air. They are altered by the sun to produce many compounds. One of these causes the stinging of the eyes, so common in photochemical smog. Ozone is a very active form of oxygen. It is also found in photochemical smog. It can cause coughing and a severe tired feeling. Lead is a metal that is added to most gasolines in the form of tetraethyl lead. Some lead is released into the air when the engine is running. It is present in the blood of auto mechanics and traffic policemen. It is known to be harmful to health. Young children sometimes eat flakes of lead paint from the walls of old houses. This can lead to severe poisoning. Although lead paint does not pollute the air, it is prohibited for painting apartments in New York, Chicago and many other cities in the world because children may swallow it.

3 Air Pollution And Ecology One of the first clues to the harmful nature of air pollution was seen in 1900 at Ducktown, Tennessee. A large refinery for copper ore was built in the mountains. The smoke from the refinery contained sulphur dioxide. After a few years, all of the trees and other plants on the hills around the refinery were killed by the gas. The soil was eroded away for miles around. The area became a desert. Now, many years later, it is impossible to restore the plant life of the region even though there is no more sulphur dioxide in the air. Ozone and sulphur dioxide have damaged plants for many miles around Los Angeles. Pine trees have been killed by photochemical smog in the mountains east of the city. Another effect has been observed near the phosphate mines in Florid Here fertilizer is made from the phosphate rocks. Clouds of smoke containing fluorides are given off by the phosphate refineries. These fluorides are taken up by plants and pass through the food chain. They pile up in plants that are eaten by cattle. The cattle sicken and die because of the large quantities of fluorides. In the same way, plants growing along roadsides pick up lead from automobile exhausts. This lead has a harmful effect on the ecology of the area around the plants. The Fight Against Air Pollution If you live in one of the hundreds of cities that have air pollution problems, you may be breathing unhealthy air during many of the days of the year. What can be done to reduce the harmful substances that are being poured out into the air? London, once one of the smoggiest cities in the world, now has much cleaner air. A law was passed prohibiting the burning of anything that would produce soot from chimneys. Only smokeless fuels were permitted. By 1962 the air was much improved. There have been no killer smogs since that time, even though there have been several temperature inversions over the city. In New York City, sulphur dioxide was a great problem. Now only low-sulphur coal and oil may be used in the city. Sulphur dioxide in the air has been reduced by more than 50 %. However, much remains to be done to control other forms of air pollution from furnaces and automobiles in the city. Soot and fumes produced by furnaces can be removed by several methods. Scrubbing sprays of water can clean up the smoke. Another method uses high voltage electricity to charge soot particles and attract them to a charged plate. The automobile is now the chief cause of air pollution. This is the most serious problem in Los Angeles. The state of California demands air pollution controls on all new automobiles sold in that state. It has been proposed that only lead-free gasoline should be used. But the exhaust fumes still contain nitrogen oxides, carbon monoxide, and other harmful substances. Although much has been done to get rid of almost all harmful fumes, such cars have not yet been perfected. Perhaps more people should use trains or buses to travel to work. The problem of air pollution is not easy to solve. But more will have to be done to prevent the poisoning of the air we all must breathe.

4 The Problem of Water Pollution A few years ago, a series of dry years occurred in the north-eastern part of the United States. Water became scarce. Many people realized for the first time how important water was to them. Water levels in the reservoirs of New York City sank lower and lower. The stored water supplies were being used up, and everyone was worried. Yet, past the very doors of the city, the Hudson River carried billions of gallons of water out to se It was so heavily polluted that it could not be used to solve the shortage. There is no shortage of water in the world, except in desert areas. But there is a serious shortage of clean water. Man is chiefly responsible for the problem of water pollution. The Story of Our Rivers Most of our large cities are built near rivers or lakes. Along the Hudson River and the Mississippi, the towns and cities are not far apart. Both of these rivers begin in hills that were once completely covered by forests. The spongy soil beneath the trees holds the water. It releases it into small streams which join to form the rivers. In the upper parts of a river the water is clear and clean. As it flows past the farms on its banks, it picks up nitrates, phosphates, and weed and insect-killing chemicals. Then it reaches the first towns along its banks. Here sewage enters the water through drainpipes. Sewage flows from toilets, home and factory drains, and street waste basins. It contains human waste, chemicals, scraps of food, and many bacteri Some of these bacteria, like the typhoid bacillus, can cause disease. But as the water flows along, the river can purify itself. Algae, bacteria, and protozoa use up the waste in the sewage and the water becomes clear again. Now the river flows past a large city. Millions of gallons of sewage are emptied into it. Factories on the river bank pour acids, dyes, oil, and other waste into the water. The river turns brown and cloudy. A bad odor rises from the water. Again the river begins to clean itself. But now large cities and industries appear more often along its banks. There are no more fish in the river. It is loaded with bacteria, fungi, algae, and human and factory waste. The temperature of the water is raised by hot water poured in from power plants. Detergents enter the water and the great masses of algae float downstream. The river becomes an open sewer. This description applies to parts of the Hudson, Mississippi, Detroit, and other rivers as they are today. The Treatment of Sewage How can the pollution of our waters be prevented? About 80 percent of our cities now treat their sewage before they return it to the rivers and lakes. The process uses ecological food chains to break down the sewage and returns its materials to the cycle of life. The treatment of sewage begins with the collection of waste. Drain water from each house goes through large pipes beneath the streets. These pipes lead to sewage treatment plants where the sewage is treated before it is returned into the rivers. Some Problems in Sewage Disposal Waste products from some factories may be too strong to be handled in the sewage treatment plant. They may contain mercury, acids or other harmful substances. These waste materials must be treated at the factory to make them harmless before they enter the sewage system. Sometimes factory waste escapes into rivers without treatment. This can cause great damage. Such accidents have happened in the Mississippi River above New Orleans and in the Ruhr

5 River in Germany. Poisonous waste entered the rivers from factories that were making insect sprays. In both cases, millions of fish were killed. Another problem involves getting rid of the sludge left after primary treatment. New York City and some cities in New Jersey place the sludge on barges. It is then towed 12 miles out to sea and dumped into the water. After many years, this created a "dead sea" off the New Jersey coast. The bacteria in the sludge have used up oxygen at the sea bottom and few living things can exist there. A good way of handling sludge is to use it for secondary treatment. After that, it is safe to use it as a fertilizer. Some towns pump it over fields and grow crops. The city of Milwaukee sells the dried sludge as fertilizer. This pays part of the cost of the sewage treatment plant. New Sources of Clean Water In many places underground water from deep wells is used. It is believed that a large body of water lies beneath the Sahara Desert. If this could be tapped, the desert could be farmed. In some areas the pumping of fresh water from the ground is creating problems in parts of California and Long Island, salt water from the sea is entering the wells as the fresh water is pumped out. As the world's population increases, the sea may be used as a new source of water. First the salt must be removed. This can be done by boiling the sea water and then condensing the water vapor. This is similar to the water cycle in nature. The heat energy for this may come from burning oil or from atomic energy. In some areas, heat from the sun could be used. Water is already being produced from the sea in the Middle East and on the island of Arub There water is scarce and there is plenty of oil for heating. The method is too expensive to be used in most places. However, new methods are being tried to bring down the cost. Other Pollution Problems The demand for energy all over the world has resulted in increased production and shipment of oil. Most of the oil is transported in huge tankers. Some of them are the largest ships afloat. If a tanker sinks or is grounded, millions of gallons of oil may escape into the se In addition, oil can escape from wells that have been drilled into the sea bottom. A number of serious accidents have already resulted in oil spillage. Sea birds have died in great numbers as their feathers became coated with greasy black oil. Undersea life has also been affected by oil spills. As the oil resources of the world are used up, we may have to turn to atomic energy for power. This creates another problem. If radiation escapes into the atmosphere, radiation pollution will occur. As we have already learned, radiation can cause mutations. Sometimes it causes cancer. Some radiation is natural. However, man has already added additional radioactive substances to the air as a result of atomic bomb tests. Unless atomic energy plants are built and run with great care, harmful radioactive substances may enter the atmosphere. Radioactive iodine 131 and strontium 90 already exist in the atmosphere. They have come from atomic bomb tests. Strontium 90 is a special problem. It has entered the ecological food chains. First taken up by plants, it has entered the bodies of cows who have eaten the plants. Human beings have swallowed it in milk. It settles in the bones of the human body. All humans born after 1961 have an average of 10 times as much strontium 90 in their bones as those born before On the tundra, the amount is even higher. Lichens pile up strontium 90 and the caribou eat the lichens. Eskimos who have eaten caribou meat have strontium 90 in their bones. In addition to sewage, cities produce many tons of trash and junk each day. Bottles, garbage, plastic bags, paper, cans, and even junked cars make up much of this waste. Solid waste is an

6 increasing problem. If it is dumped on land, it breeds rats, flies, and mosquitoes, and produces odors. One way to handle it is to make sanitary landfills. Here the trash is crushed and covered with soil. This can make land for parks and other useful purposes. But many cities are running out of space for such landfills. If solid waste could be recycled, it would yield many useful products. Already cans, bottles, and paper are being recycled in this way. Like other solutions to the pollution problem, recycling of solid waste may be expensive. However, something like it will have to be done if our environment is to be preserved. The Population Explosion Many of the world's pollution problems have been caused by the crowding of large groups of people into the cities. Providing for the needs or the people leads to further pollution by industry. All of this is damaging the biosphere. If the rapid increase in human population continues at the present rate, there may be much greater damage. Some scientists speak of the increase in numbers of people as "population pollution". About 2,000 years ago, the world population was two billion. It is now four billion. It is expected to double by the year 2,000. If the population continues to grow at the same rate, there would be 25 billion people in the world a hundred years from now! Man has been using the Earth's resources more and more rapidly over the years. Some of them are almost gone. Now many people believe that man's greatest problem is how to control the growth of his own population. The materials in the biosphere will not support the human population, in time to come, if the present rate of increase continues. Already there is overcrowding in the cities and starvation in some countries. Can man's rate of increase continue? Many people believe that human survival in the future depends on the answer to this question.

7 EXERCISES A. Make your own glossary consulting your dictionary. B. Read the following questions and before answering them read the text again. 1. What is smog? 2. Describe two killer smog disasters. 3. What is a temperature inversion? How may it cause smog? 4. How does Los Angeles smog differ from London smog? 5. How is sulphur dioxide formed? What are its harmful effects? 6. What is soot? What is the relationship between soot and cancer? 7. Where does carbon monoxide come from? Why is it dangerous? 8. What are nitrogen oxides? 9. What are the effects of ozone? 10. How may people become poisoned by lead? 11. Describe the effects of four different kinds of air pollution on plant life. 12. How is air pollution fought in London? 13. How can soot and fumes be removed from smoke? 14. How can pollution caused by automobiles be reduced? 15. What kind of materials enter rivers from farms? 16. What is sewage? 17. How does a river purify itself? 18. What happens to a river when it is overloaded with waste? 19. What are the dangers of waste produced by factories? 20. How may sludge disposal cause problems? 21. How can phosphates and nitrates be removed from sewage? 22. How does oil cause pollution? 23. What are the dangers of radiation pollution? 24. What are the problems of disposing of solid waste? 25. Describe the human population explosion. 26. What may be the results of the population explosion? C. How Does Pollution Affect Our World? discusses different kinds of pollution. The selection is an extended classification of types of pollution. Directions: Draw a diagram of the classification of pollution mentioned in this text. D. In How Pollution Affects Our World the author discusses six chemicals that pollute the air. The author says where the chemicals come from and the effects they have on people. For some of the chemicals, the author describes what has been done to reduce the pollution they cause. Fill in the chart. "Chemicals that Pollute the Air"

8 Chemical Where does it come What effect does it What has been don to from? have on people? reduce pollution caused by this chemical? E. How Does Pollution Affect Our World? explains the cause of various kinds of pollution and the effects each has on people and their environment. Directions: Prepare a chart of cause and effect. Cause Effect Air Pollution and Ecology 1. A refinery for copper was built in Tennessee. 2. Fertilizer is made from phosphate rocks in Florid Some Problems in Sewage Disposal 3. Poisonous waste from factories entered the Mississippi River and the Ruhr River. 4. Sewage plants do not treat nitrates and phosphates. Other Pollution Problems

9 5. oil spillage 6. radiation pollution 7. solid waste 8. population explosion F. Write down two specific facts or examples for each topic: Example: Chemicals which are produced every day pollute the air. When fuels which contain sulphur are burned, the sulphur mixes with the oxygen in the air and forms sulphur dioxide. Soot comes from chimneys and smoke stacks- 1. Air pollution affects the ecology of an are 2. What can be done to reduce air pollution? 3. As a river flows from the hills to the sea, it picks up many pollutants. 4. There are possible new sources of clean water. 5. There are two ways to handle the trash which cities produce every day. G. Write the topic and a topic sentence for the specific facts from "How Does Pollution Affect Our World?" Add some specific facts indicative of the paragraph. Example: Topic: killer smogs

10 Topic sentence: Smog has caused many deaths. Specific facts: In December 1930, thousands of people in Belgium became ill from a combination of smoke and fog. In 1948, 17 people in Donora, Pennsylvania, died from a killer smog. c. More than 4,000 people were killed by smog in London, England, in Topic: Topic sentence: Specific facts: c. d. Sulphur dioxide can cause bronchitis and emphysem 2. Topic: Topic sentence: Specific facts: Sulphur dioxide damages the lungs. c. d. 3. Topic: Topic sentence: Specific facts. New York permits only low-sulphur coal and oil. 4. Topic: Topic sentence: Specific facts: Sometimes factory waste escape into rivers without treatment. c. 5. Topic: Topic sentence: Specific facts: c. By 1930, the population was 2 billion. d. H. Indicate if the following statements are true (T) or false (F). Examples:

11 F Killer smogs happen frequently. T Killers smogs do not happen very often. 1. During a temperature inversion, there is a layer of cold air near the ground. 2. Photochemical smog is found only in Los Angeles. 3. Photochemical smog is rarely invisible. 4. All children in New York have lead poisoning. 5. Airports may be closed when there is a thick smog. 6. Almost all cases of lung cancer are caused by soot. 7. California insists on pollution controls on all new automobiles sold there. 8. According to federal law, cars must be run by battery power or steam engines. 9. Water in the upper parts of a river is cleaner than water in the lower parts. I. Correct the false statements. J. Write five true/false items of your own based on "How Does Pollution Affect Our World?". Use your statements to test your colleagues K. Multiple Choice Examination Questions: Directions: Circle or underline the letter next to the correct answer. Each question has only one correct answer. Example: During a temperature inversion, there is a lower layer of cold air a lower layer of warm air c. an upper layer of cold air. 1. Sulphur dioxide in the air is not related to chimneys automobiles c. paint 3. Ozone is a form of oxygen nitrogen c. sulphur 4. One good way to handle sludge is to dump it into the sea

12 use it as fertilizer c. leave it in the sediment tank 5. The "dead sea" off the New Jersey coast is caused by sludge algae c. oxygen 6. The method of producing fresh water from sea water is dangerous expensive c. complicated 7. Oil causes pollution when it is transported in tankers it is refined c. it escapes from deep-sea wells 8. is not a radioactive substance. iodine 131 strontium 90 c. sulphur dioxide 9. One problem which is not related to population pollution is overcrowding radioactivity c. starvation J. Match the words on the left with those on the right. Each item may be used more than once. air pollutants phosphates water pollutants sulphur dioxide c. land pollutants garbage typhoid bacillus junked cars nitrogen oxides nitrates carbon monoxide detergents oil K. Fill in the blanks 1. During a an upper layer of warm air keeps polluted cooler air from rising. 2. Chemicals are changed by the sun high up in the air. The result is smog. 3. is the black or grey smoke from

13 chimneys and smoke stacks. 4. break down and purify the sewage in a sewage treatment plant. 5. Using atomic energy may lead to pollution. L. Complete the following sentences. 1.A temperature inversion occurs when. 2. Salt is removed from sea water by. 3. Oil becomes a pollutant when. 4. Atomic energy creates a problem. 5. Strontium 90, which has entered the ecological food chain. 5. "Population pollution" is a problem because. M. Answer the following examination questions. 1. Enumerate the chemicals that pollute the air. 2. Illustrate the ways in which air pollution has been reduced. 3. Trace the course of a river from clean water to an open sewer. 4. Define "population pollution". N. Answer the following examination questions. 1. Every day there is more and more pollution in our world. Discuss. 2. There are no easy solutions to the pollution problems in our world. Comment. O. Answer the following questions. 1. Why do killer smogs not occur in farming areas? 2. What causes the fumes from chimneys to rise? 3. Los Angeles was the first city to order pollution controls on automobiles. Why was this so? 4. The effects of air pollution can be felt many miles from a city where it occurs. How does this happen? 5. Why is the destruction of cilia by sulphur dioxide harmful? 6. What kinds of experiments could scientists perform to find out whether soot can cause cancer? 7. Auto mechanics working in a closed garage often attach long tubes to auto exhausts. Why do they do this? 8. Why does the strong sunshine in Los Angeles make the smog worse? 9. Lead paint may not be used in making children's toys. Why not? 10. Plants are sometimes sensitive indicators of air pollution. In what way? 11. It cost a great deal of money to reduce sulphur dioxide in the air of New York City. How was the money spent? 12. People in large cities are urged to use trains instead of their own

14 cars. What good does this do? 13. During the water shortage, some thought was given to using chlorinated river water in New York City. Why wasn't this done? 14. Why do some towns dump untreated sewage into rivers? 15. What causes the bad odors from polluted waters? 16. Why does bubbling air through sewage help purify it? 17. How could heat from the sun be used to remove the salt from sea water? 18. Floating oil often kills sea birds. How does it do this? 19. It has been suggested that all atomic power plants should be built underground. What is the reason for this? 20. How can open garbage dumps spread disease? 21. It may be possible to produce food from algae or other sources to feed many more people in the future. Will this solve the population problem? Discuss. 22. One theory states that population increases will be balanced by war and disease. Do you agree? Support your answer.