CCN formation from DMS oxidation without SO2 acting as an intermediate

Abstract

An alternate pathway for generating cloud condensation nuclei (CCN) in the remote marine boundary layer (MBL) from the oxidation of biogenically‐derived dimethyl sulfide (DMS) is proposed. This pathway invokes the production of H2SO4 from DMS without SO2 serving as an intermediate in the oxidation sequence. The H2SO4 thus produced then undergoes bimolecular nucleation to form tiny sulfate condensation nuclei (CN). These CN rapidly grow to sizes sufficiently large to act as CCN. While CCN production from SO2 appears to be inefficient, model calculations indicate that the alternate pathway is capable of generating significant numbers of new CCN in the MBL within a two to three day time period. The alternate pathway also suggests a strong coupling between oceanic emissions of DMS and the number of CCN in the MBL.