|MadSci Network: Environment & Ecology|
There is currently much debate about the effects of high flying aircraft. On the one hand, these aircraft introduce NOx into the stratosphere (NO and NO2). While NOx themselves are involved in catalytic ozone depletion, they also combine with Cl and ClO to form Chlorine Nitrate, a reservoir of stratospherinc inorganic chlorine. So whether or not NOx introduction would increase or decrease overall ozone depletion depends on temperature, the rates of the individual reactions, and the relative abundance of the NOx and chlorine species. I think, perhaps, you might misunderstand what an atmospheric aerosol is. An aerosol is pretty much any particle in the gas phase. This might include things as big as hail or meteors or things as small as cloud particles or molecules. The reason aerosol sprays are bad is because they often containt CFC's. These chlorine containing compounds dissociate in the stratosphere and release chlorine there. This chlorine does not turn into chlorine nitrate until it reacts with NO2. But before it does turn to NO2, bot the NO2 and Chlorine compound (ClO) are involved in catalytic ozone destruction. And even after ClONO2 forms, it can photolyze back to their constituents. So the answer to your questions is, it depends. The other concern of high flying aircrafts is their release of particulates (aerosols) like soot and other combustion products. Heterogeneous reactions (reactions on more than one phase liquid-gas, gas-solid...) can then take place. One of the important heterogeneous reaction is the one between Chlorine Nitrate and HCl. Both are reservoirs for inorganic chlorine. But, they can react with each other on surfaces and return chlorine to their active ozone destructive states. Hope this helps.
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