Anthropogenic reactive nitrogen

Table 8 Estimates of anthropogenic reactive nitrogen production, 1990 and 2020 ...

Figure 23. Temporal trench 1950-1997) in the anthropogenic production of reactive nitrogen (Tg N/yr. = I06N tons/yr.) from fertilizer fossil fuel combustion and legume and rice cultivation (Galloway, 1998).

The SCOPE project constructed mass balance for reactive nitrogen under anthropogenic influence at the regional scale (Howarth, 1996). For inputs, for the terrestrial... 

The SCOPE project constructed a mass balance for reactive nitrogen under anthropogenic influence on the regional scale (Howarth, 1996). For inputs, for the terrestrial ecosystems the SCOPE N analysis considered application of N fertilizers, N fixation by agricultural crops, if any, NOy depositions, and import or export of N in food and animal feedstocks. Output items considered crop uptake, denitrification and volatilization and river discharge. For marine ecosystems, this analysis includes also seawater exchange. 

In contrast to sulfur species, there are no differences in principle between natural and anthropogenic processes in the formation and release of reactive nitrogen species. Industrial nitrogen fixation (in separated steps N2 NH3, N2 NOx, NOx NO3) proceeds via the same oxidation levels as biotic fixation and nitrification, either on purpose in chemical industries (ammonia synthesis, nitric acid production) or unintentionally in all high-temperature processes, namely combustion, as a byproduct due to N2 + O2 2 NO. 

Nitrogen oxide, formed by photofragmentation of N02 or chlorine nitrate (C10N02), hydroxyl radicals and some other reactive species are also responsible for stratospheric ozone depletion. These compounds may have both natural and anthropogenic (combustion, etc.) origin. Atmospheric chemistry also takes place in aerosol particles, cloud droplets1370 and ice crystals.1371,1372... 

Dinitrogen monoxide N2O is also called nitrous oxide, and emitted from natural and anthropogenic sources from the ground. Since N2O does not dissipate in the troposphere, it reaches to the stratosphere and subjects photolysis to provide reactive oxides of nitrogen (odd nitrogen). For this reason, the photolysis of N2O in the stratosphere is very important. 

---