AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Chemical Characterization of Atmospheric Semivolatile Organic Compounds in the Greater Toronto Area
MANPREET TAKHAR, Mohammad Asif Iqbal, Arthur Chan, University of Toronto
Abstract Number: 105 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Semivolatile organic compounds (SVOCs) are important for aerosol formation and air quality. Once released, SVOCs partition between gas- and particle-phases depending on atmospheric conditions such as temperature and total organic aerosol mass. Our main goal is to characterize the gas-phase and particle-phase organics present in PM$_(2.5) and relate the composition to sources and processes. Samples were collected using an Integrated Organic Gas and Particle Sampler, which includes a denuder-based gas sampler and a filter pack. Gas-phase organics were collected via sorption to the XAD-4 resin coated denuders, and particle-phase organics were collected on quartz fiber filters backed by sorbent impregnated filters (SIFs). Denuder and filter samples were collected during the 2015 Pan Am Games held in Toronto and analyzed by thermal desorption-gas chromatography mass spectrometry (TD-GC/MS) with in situ derivatization for polar organics. SVOCs like alkanes, carbonyls and fatty acid methyl esters were observed to partition between gas- and particle-phases. Volatile polycyclic aromatic hydrocarbons (PAHs) were found predominantly in the gas-phase while polycyclic aromatic compounds like quinoline, furanone, lactone, and nitriles were observed in the particle-phase. Concentrations of PAHs show positive correlation with temperature likely due to an evaporative source present in the atmosphere, whereas alkanes concentrations show no temperature dependence. Furthermore, SIFs contain both lighter and heavier alkanes likely due to breakthrough from denuders and/or evaporation from quartz filters. Polar SVOCs like levoglucosan and abietic acid which are markers for biomass burning were observed. Also, compounds like cholesterol and fatty acids, which are representative of meat cooking emissions, are characterized using in situ derivatization GC/MS. Gas-particle partitioning, volatility distribution, and fraction of organic carbon and elemental carbon present in PM$_(2.5) will also be discussed.