From Glossary of Meteorology


Abbreviation for various oxides of nitrogen, including NO (nitric oxide), NO2 (nitrogen dioxide), or N2O (nitrous oxide).

These gaseous pollutants can be transformed in the presence of water to nitric acid HNO3, one of the acids in acid deposition. They are formed anthropogenically inside combustion engines, where the ambient nitrogen N2 and oxygen O2 gases in the atmosphere can react at high temperatures. They are also produced naturally by lightning and by biological activity in soils.
See active nitrogen.