AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Fragmentation Patterns of Organosulfur Compounds in HR-ToF-AMS
YUNLE CHEN, Lu Xu, Elizabeth Stone, Timothy Humphry, Nga Lee Ng, Georgia Institute of Technology
Abstract Number: 216 Working Group: Effects of NOx and SO2 on BVOC Oxidation and Organic Aerosol Formation
Abstract Organosulfur compounds are ubiquitous components of secondary organic aerosols (SOA), and have been observed in both ambient measurements and laboratory chamber experiments. Due to their surface-active nature, organosulfur compounds can play a potentially important role in altering aerosol chemical and physical properties. High-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) has been extensively used in aerosol study. However, the HR-ToF-AMS’s response to organosulfur compounds is not well-understood, making the quantification of organosulfur compounds highly uncertain. Organosulfur compounds can fragment into both organic and sulfate fragments in the HR-ToF-AMS. However, typically all the sulfate fragments in the instrument are interpreted as inorganic sulfate fragments, despite that they can originate from an organic molecule. This leads to uncertainties in the quantification of organosulfur species and inorganic sulfate species, where the contribution of organosulfur compounds to total organic mass is underestimated. Here, we systematically investigated the fragmentation patterns of organosulfur compounds in HR-ToF-AMS, and contrasted them with that of inorganic sulfate compounds. Further, we studied how fragmentation patterns are related to organosulfur types, organic group structures, aerosol acidities, and organic coatings. These results will also be discussed in the context of ambient measurements and chamber experiments.