介绍： 版权归原作所有，仅供此学习，若有侵权请告知删除。
[12:11.26]The last reading.
[12:13.60]Air Pollution
[12:15.73]Air pollution consists of chemicals or particles in the air
[12:20.92]that can harm the health of humans, animals, and plants.
[12:25.22]Pollutants in the air take many forms.
[12:29.09]They can be g...

介绍： 版权归原作所有，仅供此学习，若有侵权请告知删除。
[12:11.26]The last reading.
[12:13.60]Air Pollution
[12:15.73]Air pollution consists of chemicals or particles in the air
[12:20.92]that can harm the health of humans, animals, and plants.
[12:25.22]Pollutants in the air take many forms.
[12:29.09]They can be gases, solid particles, or liquid drops.
[12:34.12]Pollution enters the Earth's atmosphere in many different ways.
[12:39.50]Most air pollution is created by people,
[12:42.80]taking the form of emissions from factories, cars, or planes.
[12:48.28]Second-hand cigarette smoke is also considered air pollution.
[12:53.42]These are all man-made sources of pollution.
[12:57.29]Some types of air pollution,
[12:59.67]such as smoke from wildfires or ash from volcanoes, occur naturally.
[13:05.12]They are called natural sources.
[13:08.22]People experience a wide range of health effects from being exposed to air pollution.
[13:14.97]Short-term effects, which are temporary,
[13:17.97]include discomfort such as irritation to the nose, throat, eyes, or skin.
[13:24.27]Long-term effects of air pollution, such as heart disease and lung cancer,
[13:29.29]can last for years or for an entire lifetime.