污染的起因英文

城市：London 原因：Humans probably first experienced harm from air pollution when they built fires in poorly ventilated caves. Since then we have gone on to pollute more of the earth's surface. Until recently, environmental pollution problems have been local and minor because of the Earth's own ability to absorb and purify minor quantities of pollutants. The industrialization of society, the introduction of motorized vehicles, and the explosion of the population, are factors contributing toward the growing air pollution problem. At this time it is urgent that we find methods to clean up the air.The primary air pollutants found in most urban areas are carbon monoxide, nitrogen oxides, sulfur oxides, hydrocarbons, and particulate matter (both solid and liquid). These pollutants are dispersed throughout the world's atmosphere in concentrations high enough to gradually cause serious health problems. Serious health problems can occur quickly when air pollutants are concentrated, such as when massive injections of sulfur dioxide and suspended particulate matter are emitted by a large volcanic eruption.Air Pollution in the HomeYou cannot escape air pollution, not even in your own home. "In 1985 the Environmental Protection Agency (EPA) reported that toxic chemicals found in the air of almost every American home are three times more likely to cause some type of cancer than outdoor air pollutants". (Miller 488) The health problems in these buildings are called "sick building syndrome". "An estimated one-fifth to one-third of all U.S. buildings are now considered "sick". (Miller 489) The EPA has found that the air in some office buildings is 100 times more polluted than the air outside. Poor ventilation causes about half of the indoor air pollution problems. The rest come from specific sources such as copying machines, electrical and telephone cables, mold and microbe-harboring air conditioning systems and ducts, cleaning fluids, cigarette smoke, carpet, latex caulk and paint, vinyl molding, linoleum tile, and building materials and furniture that emit air pollutants such as formaldehyde. A major indoor air pollutant is radon-222, a colorless, odorless, tasteless, naturally occurring radioactive gas produced by the radioactive decay of uranium-238. "According to studies by the EPA and the National Research Council, exposure to radon is second only to smoking as a cause of lung cancer". (Miller 489) Radon enters through pores and cracks in concrete when indoor air pressure is less than the pressure of gasses in the soil. Indoor air will be healthier than outdoor air if you use an energy recovery ventilator to provide a consistent supply of fresh filtered air and then seal air leaks in the shell of your home .