Definition: Oxides of Nitrogen are the direct result of combustion in the presence of atmospheric nitrogen and oxygen. Though they are present in the exhaust of any internal combustion engine, they are especially dominant in diesel engine emissions. A function of heat and pressure, NOx numbers skyrocket in the high compression, high temperature confines of a diesel combustion chamber. The EPA regulated portions of NOx are nitric oxide (NO) and nitrogen dioxide (NO2). These are the acidic gases that contribute to smog formation and acid rain.
Pronunciation: ŏk-sīds uhv nahy-truh-juhn
Also Known As: NOx, nitrogen oxides