What is the difference between Primary Pollutants and Secondary Pollutants ?

Primary pollutants are emitted into the atmosphere from the source, such as gases and ash from a volcanic eruption. They can be expelled in natural ways or due to human actions. Sulfur dioxide, carbon monoxide, nitrogen oxide, and chlorofluorocarbons are some primary pollutants. These pollutants cause serious environmental problems, such as global warming and acid rain.

The primary source of pollution from a central source is from motor vehicles. Secondary pollutants are directly emitted to the air by the source. Secondary pollutants are often from natural sources, and they are not emitted directly to the atmosphere, water, or soil. They are synthesized in the environment by chemical reactions involving primary or secreted chemicals. Secondary pollutants are produced by the reactions between primary pollutants and other molecules.