Investigating Aqueous Processing of Submicrometer Aerosols during the Spring HI-SCALE Campaign in the Southern Great Plains

JUSTIN TROUSDELL, John Shilling, Jerome Fast, Qi Zhang, University of California, Davis

     Abstract Number: 349
     Working Group: Source Apportionment

Abstract
Aqueous phase chemistry of organic compounds in the atmosphere has been recognized as an important source of secondary organic aerosol (SOA), which has implications for both human health and climate. As a part of the ongoing effort to understand aqueous SOA (aqSOA), we performed a comprehensive analysis of data collected by a high-resolution aerosol mass spectrometer (HR-AMS) during the DOE-sponsored Holistic Interactions of Shallow Clouds, Aerosols, and Land Ecosystems (HI-SCALE) campaign at the Southern Great Plains (SGP) site in northern Oklahoma in the spring of 2016. We applied positive matrix factorization (PMF) on a combined matrix of organic and select inorganic ions to isolate distinct SOA factors. A seven-factor solution was found to be the most appropriate environmentally. This solution included three aged biomass burning organic aerosol (BBOA) factors, a biogenic-SOA (BSOA) factor, an aged primary emission OA, an ammonium nitrate (AN) factor and an ammonium sulfate (AS) factor. Both the AN and the AS factor were mixed with oxygenated organic aerosol (OOA) species, although the AS-OOA is more oxidized than the AN-OOA. Available meteorological data, particle sizing data, and NR-PM1 composition were used to select four case study periods to investigate aqueous processing. These case studies provide us with a basis to investigate aqSOA and aqSOA tracer ions for use in the analysis of AMS data.