Types of Air Pollutants Criteria Air Pollutants
The criteria air pollutants are carbon monoxide, ozone, lead, nitrogen oxides, particulate matter, and sulfur dioxide. They come from a variety of sources and some of them are produced in the atmosphere. These pollutants were of greatest concern initially and still contribute substantially in many areas to the degradation of ambient air.
Toxic Air Pollutants
(See the special section on “Toxic Air Pollutants” later in this chapter)
(See the special section on “Greenhouse Gases” later in this chapter)
Stratospheric Ozone Layer Depletion
The stratospheric ozone layer is high above the earth and protects the health of humans and also the environment from the harmful ultraviolet radiation coming from the sun. It is a natural shield which is being affected by chemicals made by people. Chlorofluorocarbons used in various aerosols, such as coolants in refrigerators and air conditioners, rise into the stratosphere and reduce this necessary ozone protective layer. Other chemicals may also cause this problem.