Potential Contribution of Sulfate Production in Cumulus Cloud Droplets to Ground Level Particle Sulfur Concentrations

摘要

Relationships have been examined between the presence or absence of cumulus clouds and 3rd quarter fine particle sulfur concentrations in St. Louis. An association between the presence of cumulus clouds with SO2 conversions in droplets and incrementally higher fine particle sulfur concentrations can be demonstrated. However, diurnal patterns of fine particle sulfur concentrations in the presence of cumulus clouds are not consistent with local contributions from sulfate formation in cumulus clouds. Morning fog often occurs on the same days on which cumulus clouds form later. Reactions of SO2 in fog droplets appear to make a contribution, but do not account for the major part of the increments in fine particle sulfur concentrations associated with cumulus clouds.