HETEROGENEOUS OZONE DECOMPOSITION ON SULFURIC-ACID SURFACES AT STRATOSPHERIC TEMPERATURES

In this investigation, methods of forming sulfuric acid aerosols at stratospheric temperatures were studied, and the rate constant for the heterogeneous decomposition of ozone on sulfuric acid surfaces was determined over the temperature range 217-263 K. The ozone decomposition rate was observed to be first order in ozone concentration and frozen sulfuric acid surface area, and was found to be decreased by the presence of H2O. The measured ozone first order decay efficiencies were found to be on the order of 10-8 and 10-9 reactions per collision for pure frozen H2SO4 and 0.045 mole fraction H2SO4 in H2O respectively. The addition of A12O3 and Fe2O3 to the H2SO4 did not substantially increase the O3 decomposition rate. Based on these results it is concluded that the heterogeneous decomposition of ozone on frozen stratospheric sulfuric acid aerosol particles is of little significance in establishing stratospheric ozone concentrations. © 1979.