Global modeling of heterogeneous hydroxymethanesulfonate chemistry

Abstract. Hydroxymethanesulfonate (HMS) has recently been identified as an abundant organosulfur compound in aerosols during winter haze episodes northern China. It also detected other regions although the concentrations are low. Because of sparse field measurements, global significance HMS and its spatial seasonal patterns remain unclear. Here, we modify add to implementation chemistry GEOS-Chem chemical transport model conduct multiple simulations. The accounts for cloud entrainment gas–aqueous mass transfer within rate expressions heterogeneous sulfur chemistry. Our simulations can generally reproduce quantitative observations from Beijing show that East Asia highest concentration, followed by Europe North America. simulated shows a pattern with higher values colder period. Photochemical oxidizing capacity affects competition formaldehyde oxidants (such ozone hydrogen peroxide) dioxide is key factor influencing seasonality HMS. average concentration (1–3 µg m?3) ? sulfate molar ratio (0.1–0.2) found China winter. suggest aqueous clouds act major medium while aerosol liquid water may play role if constant formation greatly enhanced compared water.