Abstract
The predominant volatile sulfur compound in open ocean waters is dimethyl sulfide, representing almost 90% of the marine S emissions. Methanesulfonic acid (MSA), one of the oxidation products of dimethyl sulfide, is consequently an important constituent of marine aerosols. Laser microprobe mass analysis was used for single-particle analysis of samples collected in the marine boundary layer. MSA, like the non-sea salt sulfate, is mainly associated with the smallest aerosol particles, whose laser microprobe mass analysis spectra match the reference fingerprint spectra of MSA salts, sodium methanesulfonate, and ammonium methanesulfonate. The presence of nitrate and heavy metal ions in the spectra can reveal the degree of air pollution at the time of sampling.