题目内容
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Killer smog will also happen in the suburbs if ______ .
A．there are too many cars
B．it is too densely populated
C．it is always cloudy
D．too many factories are built
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The Killer Smog
Cases of Killer Smogs
On the night of December 1st, 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 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 of 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 the 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 diseases 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 types of smogs since 1950. 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.
Causes of Killer Smogs
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 sulfur dioxide, soot particles, and other chemicals. The smog may be so thick that airports are closed and chains of collisions 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 changed by the sun's rays. Added to these are sulfur dioxide and other fumes from factories and oil refineries. Photochemical smog is found in many large cities all over the world.
Harmful Substances Found in Smogs
Killer smogs don't 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 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.
Sulfur dioxide is formed when fuels containing sulfur are burned. The sulfur combines with the oxygen in the air to form. sulfur dioxide. This gas probably caused most of the deaths in the killer smogs. It combines with the water droplets in the air, o
A．Y
B．N
C．NG
New York City has had several London type smog since 1950. Each time there were from 100 to 400 deaths caused by the smog.
In all the killer smog, 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 rising. The harmful fumes piles up and make people iii. These fumes contain sulfur dioxide, soot particles, and other chemicals. The smog may be so thick that airports are closed and chains of collisions 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 up in the air, Los Angeles smog is called Photochemical smog. It contains automobile exhaust fumes and nitrogen oxides changed by the sun' s rays. Added to these are sulfur dioxide and other fumes from factories of oil refineries. Photochemical smog is found in many large cities all over the world.
Killer smog doesn' t happen very often, fortunately. But in many large cities, a combination of automobiles exhaust fumes, home furnace smoke, and factory waste gases pours into the air. This may also happen in the suburbs in the country, where large factories have been built. A number of harmful substances have affected the health of the population.
All of the following together form. smog Except ______ .
A．smoke and fumes
B．snow
C．water drops
D．fog
根据以下材料，回答题
Air Pollution
There is no question that the old style. of air pollution could kill people. In one week following the infamous "peasouper" fog in December 1952，4，700 people died in London. Most of these people were elderly and already had heart or lung diseases. A series of these killer fogs eventually led to the British Parliament passing the Clean Air Act which restricted the burning of coal.
Fortunately， the effect of smog on the lungs is not so dramatic. Scientists have now conducted a number of laboratory experiments in which volunteers are exposed to ozone inside a steel chamber for a few hours. Even at quite low concentrations there is a rewrsible fall in lung function，an increase in the irritability of the lungs and evidence of airway inflammation. Although irritable and inflamed lungs are particularly seen in people with asthma（哮喘 ）and other lung diseases， theseeffects of ozone also occur in healthy subjects. Similar changes are also seen after exposure to nitrogen dioxide， although there is some disagreement about the concentration at which they occur.
Other studies have found that people living in areas with high levels of pollution have more symptoms and worse lung function than those living in areas with clean air. Groups of children attending school camps show falls in lung function even at quite low concentrations of ozone.
There is also a relationship between ozone levels and hospital admissions for asthma， both in North America and Australia. It is suspected that long-term exposure to smog may result in chronic bronchitis （支气管炎） and emphysema （肺气肿） ， but this has yet to be proven.
Recently an association has been found between the levels of particles in the air and death rates in North American cities. The reason for this association is not understood and as yet there is no evidence this occurs in Australia. However， we do know that hazy days are associated with more asthma attacks in children.
Which of the following is NOT the result of laboratory experience？ 查看材料
A.Low concentrations.
B.Fall in lung function.
C.Irritability of the lungs.
D.Airway inflammation.
Smog has become the most serious type of pollution.
A．Y
B．N
C．NG
The smog spread to neighbouring countries.
A．Right
B．Wrong
C．Not mentioned
The smog spread to neighbouring countries．
A．Right
B．Wrong
C．Not mentioned
The word "smog" first appeared in 1952.
A．Right
B．Wrong
C． Not mentioned
Photochemical smog exists mainly in big cities.
A．Y
B．N
C．NG
The smog is due ______ invisible gases, mostly from automobile exhaust.
A．from
B．to
C．for
D．with
