nitrogen oxides

Oxides formed and released in all common types of combustion; they are formed by the oxidation of atmospheric nitrogen at high temperatures. Introduced into the atmosphere from car exhausts, furnace stacks, incinerators, power stations and similar sources, the oxides include nitrous oxide, nitric oxide, nitrogen dioxide, nitrogen pentoxide and nitric acid. The oxides of nitrogen undergo many reactions in the atmosphere to form photochemical smog. (Source: GILP96)