Title: Reaction of N<sub>2</sub>O<sub>5</sub> on tropospheric aerosols: Impact on the global distributions of NO<sub><i>x</i></sub>, O<sub>3</sub>, and OH
Abstract: Using a three‐dimensional global model of the troposphere, we show that the heterogeneous reactions of NO 3 and N 2 O 5 on aerosol particles have a substantial influence on the concentrations of NO x , O 3 , and OH. Due to these reactions, the modeled yearly average global NO x burden decreases by 50% (80% in winter and 20% in summer). The heterogeneous removal of NO x in the northern hemisphere (NH) is dominated by reactions on aerosols; in the tropics and southern hemisphere (SH), with substantial smaller aerosol concentrations, liquid water clouds can provide an additional sink for N 2 O 5 and NO 3 . During spring in the NH subtropics and at mid‐latitudes, O 3 ‐concentrations are lowered by 25%. In winter and spring in the subtropics of the NH calculated OH concentrations decreased by up to 30%. Global tropospheric average O 3 and OH burden (the latter weighted with the amount of methane reacting with OH) can drop by about 9% each. By including reactions on aerosols, we are better able to simulate observed nitrate wet deposition patterns in North America and Europe. O 3 concentrations in springtime smog situations are shown to be affected by heterogeneous reactions, indicating the great importance of chemical interactions resulting from NO x and SO 2 emissions. However, a preliminary analysis shows that under present conditions a change in aerosol concentrations due to limited SO 2 emission control strategies (e.g., reductions by a factor of 2 in industrial areas) will have only a relatively minor influence on O 3 concentrations. Much larger reductions in SO 2 emissions may cause larger increases in surface O 3 concentrations, up to a maximum of 15%, if they are not accompanied by a reduction in NO x or hydrocarbon emission.
Publication Year: 1993
Publication Date: 1993-04-20
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 688
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