INSITU MEASUREMENTS CONSTRAINING THE ROLE OF SULFATE AEROSOLS IN MIDLATITUDE OZONE DEPLETION

In situ measurements of stratospheric sulphate aerosol, reactive nitro gen and chlorine concentrations at middle latitudes confirm the import ance of aerosol surface reactions that convert active nitrogen to a le ss active, reservoir form. This makes mid-latitude stratospheric ozone less vulnerable to active nitrogen and more vulnerable to chlorine sp ecies. The effect of aerosol reactions on active nitrogen depends on g as phase reaction rates, so that increases in aerosol concentration fo llowing volcanic eruptions will have only a limited effect on ozone de pletion at these latitudes.