Air pollution is a problem everywhere in the world. Local air pollution usually affects big cities. Air pollution becomes a worldwide problem when local pollution moves away from where it came from. For example, winds carry air pollution made in the middle of the western part of the United States to Canada, like acid precipitation.
Acid precipitation
Acid precipitation is precipitation, like rain, sleet, or snow, that contains acids from air pollution. When fossil fuels are burned, they let out oxides into the air. When these oxides mix with water in the atmosphere, they make acid, which fall as precipitation.[1] Acid precipitation can kill living things, like fish and trees, by making the place where they live too acidic. Acid rain can also damage buildings made of limestone and concrete.
Ozone hole
Other global concerns because of air pollution include the greenhouse gases and the hole in the ozone layer in the stratosphere. The Earth's ozone layer is supposed to protect people from the Sun's harmful ultraviolet rays, but in the 1970s, scientists found out that some chemicals let out into the atmosphere makes the ozone turn into oxygen, which means that more ultraviolet rays reach the Earth. During the 1980s, scientists found that the ozone layer above the South Pole had thinned by 50 to 98 percent.
Human health[change | edit source]
On March 17, 1992, in Mexico City, all children under the age of 14 could not go to school because of air pollution. This does not often happen, but being exposed to air pollution every day can make people have many health problems. Children, elderly (old) people, and people with allergies especially, can have a lot of problems because of air pollution. Studies from the University of Birmingham showed that deaths because of pneumonia and air pollution from motor vehicles like cars are related.[2] The World Health Organization said that 2.4 million people died because of the direct problems of air