Primary Pollutant V/s Secondary Pollutant

Primary pollutant	Secondary Pollutant
1.    Primary pollutants are the pollutants that are emitted directly from the sources and are found in the atmosphere in the form in which they were emitted. 2.    Examples: Ash, smoke, radioactive compounds, oxides of sulphur etc.	1.    Secondary pollutants are the pollutants that are formed in the atmosphere by chemical reactions between primary pollutants and atmospheric constituents. 2.    Examples: SO3 m O3 , Ketones, Peroxyacetyl nitrate.