Ozone is classified as a secondary pollutant. identify the primary pollutants

These are pollutant compounds that come directly out of the exhaust pipe, natural emission sources such as carbon monoxide, carbon dioxide, sulfur oxide, sulfure dioxide, nitrogen oxide and other. Primary pollutants are usually transformed by the presence of sunlight, water and energy into secondary pollutants. It does not occur rapidly at night compared during day time. These means that to control secondary pollutants, primary pollutants must be controlled.