Unseen Impacts of Organic Sulfur from Lower Sulfur Dioxide on Air Quality and Aerosol Properties
Abstract
Atmospheric oxidation of isoprene, the most abundant non-methane hydrocarbon emitted by vegetation, yields large quantities of epoxydiols (IEPOX). Acid-catalyzed multiphase reaction of IEPOX with sulfate aerosol produces substantial amounts of secondary organic aerosol (SOA). The central role of acidic sulfate in producing IEPOX-derived SOA is through conversion of inorganic sulfate to organosulfur. We show that the extent of conversion is a positive function of the IEPOX-to-inorganic sulfate ratio (IEPOX:SO42-) and can be up to 90% at high, but atmospherically relevant values of this ratio. Furthermore, we show that the extent of conversion influences the physicochemical properties of atmospheric fine particles, such as acidity, morphology, phase state, and climate forcing. As pollution controls reduce SO2 emissions and thereby increases the IEPOX:SO42- ratio, the heterogeneous chemical conversion of inorganic sulfate to organosulfur likely plays a stronger role in SOA's potential effects on regional climate.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A43D..01S
- Keywords:
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- 0317 Chemical kinetic and photochemical properties;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0340 Middle atmosphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0365 Troposphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0394 Instruments and techniques;
- ATMOSPHERIC COMPOSITION AND STRUCTURE