【托福阅读素材】空气污染问题

新东方网>广州新东方学校>出国留学>北美>TOEFL（托福）>正文

【托福阅读素材】空气污染问题

2016-07-29 15:12

来源：

作者：新东方广州学校

分享到

摘要：广州新东方学校 22年专注教育培训，校区遍布广州各区，课程涵盖出国留学、英语学习、考研辅导、中学辅导、小学辅导、小语种等，是一所综合性教育培训学校。所有课程均可网报，更多优惠可咨询电话：400-020-9198

当前所在位置：广州新东方学校>>>出国留学>>>北美>>>托福(TOEFL)

点击查看>>>2016年TOEFL（托福）备考特辑

Air Pollution

　　Comes From Many Sources

　　Here's what you need to know about the warming planet, how it's affecting us, and what's at stake.

　　Smog hanging over cities is the most familiar and obvious form of air pollution. But there are different kinds of pollution—some visible, some invisible—that contribute to global warming. Generally any substance that people introduce into the atmosphere that has damaging effects on living things and the environment is considered air pollution.

　　Carbon dioxide, a greenhouse gas, is the main pollutant that is warming Earth. Though living things emit carbon dioxide when they breathe, carbon dioxide is widely considered to be a pollutant when associated with cars, planes, power plants, and other human activities that involve the burning of fossil fuels such as gasoline and natural gas. In the past 150 years, such activities have pumped enough carbon dioxide into the atmosphere to raise its levels higher than they have been for hundreds of thousands of years.

　　Other greenhouse gases include methane—which comes from such sources as swamps and gas emitted by livestock—and chlorofluorocarbons (CFCs), which were used in refrigerants and aerosol propellants until they were banned because of their deteriorating effect on Earth's ozone layer.

　　Another pollutant associated with climate change is sulfur dioxide, a component of smog. Sulfur dioxide and closely related chemicals are known primarily as a cause of acid rain. But they also reflect light when released in the atmosphere, which keeps sunlight out and causes Earth to cool. Volcanic eruptions can spew massive amounts of sulfur dioxide into the atmosphere, sometimes causing cooling that lasts for years. In fact, volcanoes used to be the main source of atmospheric sulfur dioxide; today people are.

　　Industrialized countries have worked to reduce levels of sulfur dioxide, smog, and smoke in order to improve people's health. But a result, not predicted until recently, is that the lower sulfur dioxide levels may actually make global warming worse. Just as sulfur dioxide from volcanoes can cool the planet by blocking sunlight, cutting the amount of the compound in the atmosphere lets more sunlight through, warming the Earth. This effect is exaggerated when elevated levels of other greenhouse gases in the atmosphere trap the additional heat.

　　Most people agree that to curb global warming, a variety of measures need to be taken. On a personal level, driving and flying less, recycling, and conservation reduces a person’s "carbon footprint"—the amount of carbon dioxide a person is responsible for putting into the atmosphere.

　　On a larger scale, governments are taking measures to limit emissions of carbon dioxide and other greenhouse gases. One way is through the Kyoto Protocol, an agreement between countries that they will cut back on carbon dioxide emissions. Another method is to put taxes on carbon emissions or higher taxes on gasoline, so that people and companies will have greater incentives to conserve energy and pollute less.

了解更多托福资讯>>>托福（TOEFL）

推荐阅读

【托福听力】托福听力备考最简单粗暴的方法

【托福写作】作文写得慢怎么破？

【托福阅读素材】埃及罗塞塔石碑

新东方广州学校官方咨询微信：小小新：（微信号：gzxdfsc）

了解更多优惠活动、课程安排，欢迎添加我们的微信号【gzxdfsc】，
这里将随时有顾问提供专业课程咨询和优惠发送，感谢您对新东方的支持。

焦点推荐

版权及免责声明

① 凡本网注明"稿件来源：新东方"的所有文字、图片和音视频稿件，版权均属新东方教育科技集团（含本网和新东方网）所有，任何媒体、网站或个人未经本网协议授权不得转载、链接、转贴或以其他任何方式复制、发表。已经本网协议授权的媒体、网站，在下载使用时必须注明"稿件来源：新东方"，违者本网将依法追究法律责任。

② 本网未注明"稿件来源：新东方"的文/图等稿件均为转载稿，本网转载仅基于传递更多信息之目的，并不意味着赞同转载稿的观点或证实其内容的真实性。如其他媒体、网站或个人从本网下载使用，必须保留本网注明的"稿件来源"，并自负版权等法律责任。如擅自篡改为"稿件来源：新东方"，本网将依法追究法律责任。

③ 如本网转载稿涉及版权等问题，请作者见稿后在两周内速来电与新东方网联系，电话：010-60908555。