Modeling of ozone reactions on aircraft-related soot in the upper troposphere and lower stratosphere

Several studies in modeling atmospheric processes have suggested that heterogeneous chemistry on soot emitted from high altitude aircraft could affect stratospheric ozone depletion, However, these modeling Studies were limited because they did not adequately consider the decrease in reaction probability with time as the surface of the soot becomes "poisoned" by its interactions with various gases, Here we extend UIUC's two-dimensional chemical-transport model to investigate possible effects of heterogeneous reactions of ozone on aircraft-generated carbon particles, including a treatment of soot poisoning in the model. We generally follow literature recommendations for ozone uptake probabilities and determine the available active sites on soot given partial pressures of the reactants, temperature, and time since soot emission in order to investigate ozone decrease. The regeneration of soot active sites is also taken into account in this study. We find that, even if active sites on soot surfaces are regenerated, upper troposphere and lower stratosphere ozone losses on aircraft emitted soot occurring through heterogeneous reactions are insignificant once poisoning effects are considered. (C) 2001 Elsevier Science Ltd, All rights reserved.