How does nitrogen oxide get into the environment?
“Nitrogen oxides” (NOx) is the term used to describe the sum of nitric oxide (NO), nitrogen dioxide (NO2), and other oxides of nitrogen. Most airborne NOx comes from combustion-related emissions sources of human origin, primarily fossil fuel combustion in electrical utilities, high-temperature operations at other industrial sources, and operation of motor vehicles. However, natural sources, like biological decay processes and lightning, also contribute to airborne NOx. Fuel-burning appliances, like home heaters and gas stoves, produce substantial amounts of NOx in indoor settings (U.S. EPA, 2003).
