Heterogeneous chemistry on polar stratospheric clouds

Abstract

Polar stratospheric clouds play a crucial role in the depletion of stratospheric ozone over Antarctica in the spring months. The cloud particles promote the conversion of the inert chlorine reservoirs HCl and ClONO2 to Cl2, which is photolytically active. Furthermore, the clouds lead to the removal of nitric acid and nitrogen oxides from the gas phase, facilitating the destruction of ozone by catalytic cycles involving chlorine free radicals. © 1991.