Pollutants II

Primary pollutants produced by human activity include:

oxides of sulfur, nitrogen and carbon
organic compounds, such as hydrocarbons (fuel vapours and solvents)
particulate matter, such as smoke and dust
metal oxides, especially those of lead, cadmium, copper and iron
chlorofluorocarbons (CFCs)
hazardous air pollutants (HAP)
persistent organic pollutants (POPs)
odours
Secondary pollutants include some particles formed from gaseous primary pollutants and compounds in photochemical smog, such as nitrogen dioxide, ground level ozone and peroxyacetyl nitrate (PAN).