Author: Antonio Da Roza

Date: 12/8/10

There are two categories of air pollutant: primary pollutants and secondary pollutants. [1]

Primary pollutants are emissions from an identifiable source, such as from power plants or vehicles. Primary pollutants include sulphur dioxide, nitrogen oxides, particulate matter, carbon monoxide, lead, and volatile organic compounds. [1]

Secondary pollutants are created in the atmosphere when primary pollutants have chemical reactions with each other or other atmospheric compounds, such as water vapour. Secondary pollutants include particulate matter and ozone. [1]

List of primary pollutants

Carbon monoxide (CO)

Sulphur Dioxide (SO2)

Nitrogen oxides (NOx)

Lead (Pb)

Volatile organic compounds (VOCs)

Particulate matter (PM)*

*PM may be primary or secondary


  1. 1.0 1.1 1.2 ‘The air that we breathe’, CLSA, April 2005 - last accessed 7/8/10