Air Pollution
Air pollution consists of chemicals or particles in the air that can harm the health of humans , animals , and plants . It also damages buildings .
Air pollution consists of chemicals or particles in the air that can harm the health of humans , animals , and plants . It also damages buildings . Pollutants in the air take many forms . They can be gases , solid particles , or liquid droplets .
Sources of Air Pollution
Pollution enters the Earth ' s atmosphere in many different ways . Most air pollution is created by people , taking the form of emissions from factories , cars , planes , or aerosol cans . Second-hand cigarette smoke is also considered air pollution . These manmade sources of pollution are called anthropogenic sources .
Some types of air pollution , such as smoke from wildfires or ash from volcanoes , occur naturally . These are called natural sources .
Air pollution is most common in large cities where emissions from many different sources are concentrated . Sometimes , mountains or tall buildings prevent air pollution from spreading out . This air pollution often appears as a cloud making the air murky . It is called smog . The word " smog " comes from combining the words " smoke " and " fog ."