(c) Sulphur dioxide is not a secondary pollutant. Primary pollutants are directly emitted from the sources while secondary pollutants are not. Examples of primary pollutants are carbon monoxide, carbon dioxide, Sulphur dioxide and benzene, etc. Secondary pollutants are formed from the combination of primary pollutants and with some other compounds.Examples of secondary pollutants are ozone, Formaldehyde, PAN(peroxy acetyl nitrate), smog, etc.