OClO and BrO observations in the volcanic plume of Mt. Etna-implications on the chemistry of chlorine and bromine species in volcanic plumes

Abstract

Spatial and temporal profiles of chlorine dioxide (OClO), bromine monoxide (BrO) and sulfur dioxide (SO 214 moleculescm -2 (OClO) and 1:1 10 15 moleculescm -2 (BrO).Mean mixing ratios of BrO and OClO were estimated assuming a circular plume cross section. Furthermore, ClO mixing ratios were derived directly from the BrO and OClOSCDs. Average abundances of &Combining double low line; BrO D 1:35 ppb, &Combining double low line; OClO D 300 ppt and ClO D 139 ppt were found in the young plume (plume age τ < 4 min) with peak values of 2.7 ppb (BrO), 600 ppt (OClO) and 235 ppt (ClO) respectively.