[en] Reported in this study are the results from a gas kinetics--aerosol laboratory study involving the OH induced oxidation of SO₂. 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 (N₂) pressure has been estimated by these authors to be 9 x 10^-13cm³/molec/s. Based on estimated k values and concentrations for several trace gases, it is suggested here that the resulting HSO₃ radical from reaction (1) under atmospheric conditions would react predominantly with O₂ in both the lower stratosphere and the troposphere. It is further suggested that the product HSO₅ radical would undergo hydration in both atmospheric regions