Hygroscopicity and CCN potential of DMS-derived aerosol particles

Abstract. Dimethyl sulfide (DMS) is emitted by phytoplankton species in the oceans and constitutes largest source of naturally sulfur to atmosphere. The climate impact secondary particles, formed through oxidation DMS hydroxyl radicals, still elusive. This study investigates hygroscopicity cloud condensation nuclei activity such particles discusses results relation their chemical composition. We show that mean parameters, κ, during an experiment for 80 nm diameter range from 0.46 0.52 or higher, as measured at both sub- supersaturated water vapour conditions. Ageing leads increase κ from, example, 0.50 0.58 over course 3 h (Exp. 7). Aerosol mass spectrometer measurements this indicate change most probably stems a composition leading slightly higher fractions ammonium sulfate compared methanesulfonic acid (MSA) within with ageing time. Lowering temperature 258 K increases slightly, particularly small particles. These values are well comparable previously reported model MSA mixtures between sulfate. Particle nucleation growth rates suggest clear dependence, slower cold temperatures. Quantum calculations gas-phase clusters predominantly not hydrated, even high humidity conditions, indicating chemistry should be independent relative humidity.