【单选题】

When people think about air pollution, they usually think about smog, acid rain,CFC’’s, and other forms of outdoor air pollution.But do you know that air pollution also can exist inside homes and other buildings It can, and every year, the health of many people is affected by chemical substances present in the air within buildings.

A、great deal of research on pollution is being conducted at laboratories and universities. The goals of the research are to find solutions and to educate the public about the problem. Two places where this type of work is being done are LBNL and the University ofCalifornia,Berkeley. Let’’s take a closer look at the various types of air pollution, the effects that they have on people, and what is being (or not being) done to correct the problem.What isAir Pollution Air is the ocean we breathe.Air supplies us with oxygen which is essential for our bodies to live.Air supplies us with oxygen which is essential for our bodies to live.Air is 99.9% nitrogen (氮气), oxygen, water vapor and inert(惰性的) gases. Human activities can release substances into the air, some of which can cause problems for humans, plants, and animals.There are several main types of pollution and well-known effects of pollution which are commonly discusseD、These include smog, acid rain, the greenhouse effect, and "holes" in the ozone layer.Each of these problems has serious implications for our health and well-being as well as for the whole environment.One type of air pollution is the release of particles (微粒) into the air from burning fuel for energy.Diesel smoke (柴油烟) is a good example of this particulate matter. The particles are very small pieces of matter measuring about 2.5 microns or about .0001 inches. This type of pollution is sometimes referred to as "black carbon" pollution. The exhaust from burning fuels in automobiles, homes, and industries is a major source of pollution in the air. Some authorities believe that even the burning of wood and charcoal (木炭) in fireplaces and barbeques can release significant quantities of soot (油烟) into the air. Another type of pollution is the release of noxious gases, such as sulfur dioxide, carbon monoxide, nitrogen oxides, and chemical vapors. These can take part in further chemical reactions once they are in the atmosphere, forming smog and acid rain.Pollution also needs to be considered inside our homes, offices, and schools. Some of these pollutants can be created by indoor activities such as smoking and cooking. In the United States, we spend about 80-90% of our time inside buildings, and so our exposure to harmful indoor pollutants can be serious. It is therefore important to consider both indoor and outdoor air pollution.OutdoorAir PollutionSmog is a type of large-scale outdoor pollution. It is caused by chemical reactions between pollutants derived from different sources, primarily automobile exhaust and industrial emissions.Cities are often centers of these types of activities, and many suffer from the effects of smog, especially during the warm months of the year.Additional information about smog and its effects are available from theAir Quality ManagementDistrictAQMD、in southernCaliforni
A、For each city, the exact causes of pollution may be different.Depending on the geographical location, temperature, wind and weather factors, pollution is dispersed differently. However, sometimes this does not happen and the pollution can build up to dangerous levels.
A、temperature inversion occurs when air close to the earth is cooler is 99.9% nitrogen (氮气), oxygen, water vapor and inert(惰性的) gases. Human activities can release substances into the air, some of which can cause problems for humans, plants, and animals.There are several main types of pollution and well-known effects of pollution which are commonly discusseD、These include smog, acid rain, the greenhouse effect, and "holes" in the ozone layer.Each of these proble