What is Air Pollution?
If there are other particles or gases in the air that are not part of its normal composition, we call this “air pollution” and the particles or gases are called “air pollutants.” Very small amounts of certain air pollutants can cause serious health and environmental problems. We can see some air pollutants such as the reddish-brown haze in smog; however, other air pollutants, including some of the most dangerous, are invisible. Air pollution can be natural or human-made. Air pollution occurs naturally during volcano eruptions, forest fires, or dust storms. This has been an occasional problem for humans. However, during the past hundred years, air pollution created by humans has become a major, persistant problem. In California, our cities are among the smoggiest urban areas in the country.
Air is primarily oxygen, nitrogen, and small amounts of other gases. Air pollution develops when human activity and natural sources affect this gaseous mix. Three main sources pollute these gases: • Sources that don t move: these include factories, refineries, and power plants. These are called point sources because they can be traced to a single point or location. • Sources that do move: these include cars, construction equipment, lawn mowers, all terrain vehicles, and boats. These are called mobile or nonpoint sources because the cannot be traced to a single point or location. • Sources that grow naturally: these include trees and grass and flowers. They are called biogenic sources.
The air we breathe is made up of a mixture of gases and small particles. Pollutants in the air are chemicals or substances that are harmful to humans, other species, or ecosystems as a whole. These such pollutants can come from human (anthropogenic) sources, or from natural sources such as volcanos or dust storms. For more information visit the Weather Underground’s main air pollution page.
Clean air is a mixture of nitrogen and oxygen, with less than 1 percent carbon dioxide, argon, and other gases—along with varying amounts of water vapor. Even small amounts of particles and gases, called air pollutants, that are not part of this normal composition can cause us serious health and environmental problems. Air pollution is a problem in many areas of the United States. It can damage trees and lakes, and make people and animals sick. It can also damage buildings and other structures. Air pollution can cause haze, reducing visibility in national parks and sometimes interfering with aviation. The federal government regulates air pollution in order to protect human health and the environment.
