Earth, Space, and Environmental Chemistry

Rising Importance of Organosulfur Species for Aerosol Properties and Future Air Quality

Abstract

Acid-driven multiphase chemistry of isoprene epoxydiols (IEPOX), a key isoprene oxidation product, with inorganic sulfate aerosol yields substantial amounts of secondary organic aerosol (SOA) through the formation of organosulfur. The extent and implications of inorganic-to-organic sulfate conversion, however, are unknown. Herein, we reveal that extensive consumption of inorganic sulfate occurs, which increases with the IEPOX-to-inorganic sulfate ratio (IEPOX:Sulfinorg), as determined by laboratory and field measurements. We further demonstrate that organosulfur greatly modifies critical aerosol properties, such as acidity, morphology, viscosity, and phase state. These new mechanistic insights reveal that changes in SO2 emissions, especially in isoprene-dominated environments, will significantly alter biogenic SOA physicochemical properties. Consequently, IEPOX:Sulfinorg will play a central role in understanding historical climate and determining future impacts of biogenic SOA on global climate and air quality.

Content

Thumbnail image of Organosulfur_2019_manuscript.pdf

Supplementary material

Thumbnail image of Organosulfur_2019_SI.pdf
Organosulfur 2019 SI