On the potential importance of sulfur-induced activation of soot particles in nascent jet aircraft exhaust plumes1

The chemical conversion of emitted SO2 and SO3 to gaseous H2SO4 in nascent aircraft exhaust plumes and subsequent adsorption of the fully oxidized sulfur species on the surfaces of emitted combustion aerosols (soot) is investigated. Results are presented for the mass fractions of SO3 and H2SO4 acquired per soot particle early in the plume, suggesting that sulfur-induced activation is an efficient pathway to increase the ability of exhaust soot emitted at altitude to host heterogeneous chemical reactions and to trigger the formation of cirrus clouds.