AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Comprehensive Characterization of Fine Particulate Matter from Southeastern United States: Implications for Composition, Origins, and Atmospheric Processing of Organic Aerosol
HAOFEI ZHANG, Lindsay Yee, David Worton, Gabriel Isaacman-VanWertz, Nathan Kreisberg, Steven Spielman, Susanne Hering, Allen H. Goldstein, University of California, Berkeley
Abstract Number: 217 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Chemically characterizing atmospheric organic aerosol (OA) composition is crucial to elucidating their origins and formation pathways, but also very challenging due to the chemical complexity in atmospheric aerosol samples. In this work, 254 ambient aerosol samples were collected at 4-hour time resolution by a customized sequential air sampler at Centerville, Alabama, United States, during the Southern Oxidant and Aerosol Study (SOAS). The samples were analyzed using a Thermal Desorption Two-Dimensional Gas Chromatography High-resolution Time-Of-Flight Mass Spectrometer (TD-2DGC-HTOF-MS) with on-line trimethylsilylation derivatization to obtain clear chemical separation with extensive ranges of volatility and polarity. Timelines were created for approximately 700 organic tracers, 10-20% of which are known species, including primary OA (POA) and secondary OA (SOA) chemicals with known anthropogenic and biogenic origins. Positive matrix factorization (PMF) analysis was performed to identify major OA sources and transformation processes, including association of a much more complete range of identified and unidentified tracers with specific factors than has previously been possible. The time series of all compounds are compared with co-located on-line measurements, including on-line Thermal desorption Aerosol Gas chromatograph (TAG), Aerosol Mass Spectrometer (AMS), and the AMS-resolved PMF factors. The origins and identifications of some previously unknown compounds are reported from ambient observations for the first time. The atmospheric processing that leads to the formation and evolution of these OA are also suggested.