Greenhouse effect of NOX

Through various processes the nitrogen oxides (NO_X) interact with trace gases in the troposphere and stratosphere which do absorb in the spectral range relevant to the greenhouse effect (infrared wavelengths). The net effect is an enhancement of the greenhouse effect. The catalytic role of NO_X in the production of tropospheric ozone provides the most prominent contribution. The global waming potential is estimated as GWP (NO_X = 30 – 33 and 7 – 10 for the respective time horizons of 20 and 100 years, and is thereby comparable to that of methane. NO_X emissions in rural areas of anthropogenically influenced regions, or those in the vicinity of the txopopause caused by air traffic, cause the greenhouse effectivity to be substantially more intense. We estimate an additional 5–23 % for Germany’s contribution to the anthropogenic greenhouse effect as a result of the indirect greenhouse effects stemming from NO_X. Furthermore, a small and still inaccurately defined amount of the deposited NO_X which has primarily been converted into nitrates is again released from the soil into the atmosphere in the form of the long-lived greenhouse gas nitrous oxide (N₂O). Thus, anthropogenically induced NO_X emissions contribute to enhanced greenhouse effect and to stratospheric ozone depletion in the time scale of more than a century.