The effect of the HO2+NO reaction rate constant on one-dimensional model calculations of stratospheric ozone perturbations

With the aid of a one-dimensional steady-state, stratospheric model we have calculated ozone changes coused by atmosphric injections of NO_x, N₂O and chlorofluoromethanes. Adopting the fast rate constant, for the reaction HO₂+NO»OH+NO₂ measured by Howard and Evenson, we calculate much smaller perturbations of the ozone layer by NO_x and N₂O additions than previously estimated, but about two times larger ozone reductions as a result of continued emissions of chlorofluoromethanes, CF₂Cl₂ and CFCl₃.The model results are sensitive to adopted values for the rate coefficients for the reactions HO₂+O₃»OH+2O₂ and OH+HO₂»H₂O+O₂ and the eddy diffusion profile near the tropopause. More accurate assessments of ozone perturbations require the development of photochemical models that incorporate meteorological processes in more than one dimension.