Read the following text and choose the most suitable heading from A-F for each paragraph.

Read the following text and choose the most suitable heading from A-F for each paragraph. There is one extra heading which you do not need.
A. Factors that influence reactions to pollutants
B. Possible sources of indoor air pollution
C. Ways to identify diseases with similar symptoms
D. Long-term effects after repeated exposure
E. A commonly-ignored health threat
F. Immediate symptoms and regular treatment
【小题1】Most people are aware that outdoor air pollution can damage their health, but many do not know that indoor air pollution can also have significant health effects. Environmental Protection Agency studies indicate that indoor levels of pollutants may be 2-5 times, and occasionally more than 100 times, higher than outdoor levels. These levels of indoor air pollutants may be of particular concern because most people spend about 90％ of their time indoors.
【小题2】There are many sources of indoor air pollution in any home. These include combustion sources such as oil, gas, coal, wood, and tobacco products; building materials and furnishings as diverse as deteriorated asbestos-containing insulation, wet or damp carpet, and cabinetry or furniture made of certain pressed wood products; products for household cleaning and maintenance, personal care, or hobbies; central heating and cooling systems and humidification devices; and outdoor sources such as radon, pesticides, and outdoor air pollution.
【小题3】Immediate effects may show up after a single exposure or repeated exposures. These include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. Such immediate effects are usually short-term and treatable. Sometimes the treatment is simply eliminating the person's exposure to the source of the pollution, if it can be identified. Symptoms of some diseases, including asthma, hypersensitivity and fever, may also show up soon after exposure to some indoor air pollutants.
【小题4】The likelihood of immediate reactions to indoor air pollutants depends on several factors. Age and pre-existing medical conditions are two important influences. In other cases, whether a person reacts to a pollutant depends on individual sensitivity, which varies tremendously from person to person. Some people can become sensitized to biological pollutants after repeated exposures, and it appears that some people can become sensitized to chemical pollutants as well.
【小题5】Certain immediate effects are similar to those from colds or other viral diseases, so it is often difficult to determine if the symptoms are a result of exposure to indoor air pollution. For this reason, it is important to pay attention to the time and place the symptoms occur. If the symptoms fade or go away when a person is away from the home and return when the person returns, an effort should be made to identify indoor air sources that may be possible causes. E

(答案→)E 解析：本文讲述了另外一种我们常常忽视的污染—室内空气污染。分析了原因讲述了具体的症状。【小题1】E 根据本段第二行but many do not know that indoor air pollution can also have significant health effects.可知本文讲述的是室内污染的话题，故E项正确。【小题2】B 根据本段第一句There are many sources of indoor air pollution in any home.可知本段讲述的是室内空气污染的来源。故B正确。【小题3】F 根据1,3行Immediate effects may show up after a single exposure or repeated exposureSuch immediate effects are usually short-term and treatable.可知本文讲述的是症状和治疗的方法。故F正确。【小题4】A 根据本段第一句】The likelihood of immediate reactions to indoor air pollutants depends on several factors可知本段是关于影响这些污染物的多个因素。【小题5】C 根据本段第一句】Certain immediate effects are similar to those from colds or other viral diseases, so it is often difficult to determine if the symptoms are a result of exposure to indoor air pollution.可知讲述的是辨别和室内污染有类似症状的疾病的方法。

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