Evidence for a short tropospheric residence time for carbon disulfide

Abstract

Our recent measurements of the concentrations of CS 2 in the background troposphere suggest that the atmospheric residence time of this substance is short, probably on the order of ten days. This conclusion is based on the very low CS 2 concentrations found in the free troposphere (<3 pptv) and the relatively large concentrations (30 pptv) found in the boundary layer. Such a rapid decrease in concentration with altitude can be explained in a straightforward way only if the residence time of CS 2 is less than the characteristic vertical mixing time of the troposphere, which is of the order of ten days.