Primary pollutants are pollutants that come directly from a source. Secondary pollutants are the result of primary pollutants reacting with the environment and creating a new pollutant.
Primary pollutant examples: carbon and nitrogen oxides, sulfur dioxide, hydrocarbons, particulates
Secondary pollutant examples: sulfur trioxide, PAN, nitrogen oxide salts, ozone
Primary pollutant examples: carbon and nitrogen oxides, sulfur dioxide, hydrocarbons, particulates
Secondary pollutant examples: sulfur trioxide, PAN, nitrogen oxide salts, ozone