What is Air Pollution?
What is air pollution?
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.