SO 2 oxidation via the hydroxyl radical: Atmospheric fate of HSOx radicals

Reported in this study are the results from a gas kinetics — aerosol laboratory study involving the OH induced oxidation of SO 2 . At tropospheric and lower stratospheric pressures, reaction (1) is neither a third order process nor is it a simple bimolecular reaction. The effective bimolecular k value at one atmosphere (N 2 ) pressure has been estimated by these authors to be 9 × 10 −13 cm³/molec/s. Based on estimated k values and concentrations for several trace gases, it is suggested here that the resulting HSO 3 radical from reaction (1) under atmospheric conditions would react predominantly with O 2 in both the lower stratosphere and the troposphere. It is further suggested that the product HSO 5 radical would undergo hydration in both atmospheric regions.