10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Gas-Particle Partitioning of the Traffic-Emitted Semi-Volatile Organic Compounds Measured in Fort McHenry Road Tunnel
CHIRANJIVI BHATTARAI, Andrey Khlystov, Desert Research Institude
Abstract Number: 1418 Working Group: Aerosol Chemistry
Abstract The volatility of ambient organic aerosol compounds is essential to understanding their contribution to ambient particulate matter (PM) concentrations, their atmospheric lifetime, and their effect on human health. Only recently it has been realized that primary organic aerosols (POA), such as those emitted by vehicular traffic, contain a large fraction of semivolatile substances. Data on volatility of individual semi-volatile compounds emitted by traffic is still scarce. We have sampled gas and particles phase semi-volatile organic compounds (SVOC) using Teflon-impregnated glass fiber filters (TIGF) and XAD-4 resin at Fort McHenry Tunnel (Baltimore, MD, USA) in February and August 2015 to estimate the saturation vapor pressure of about 100 individual semi-volatile organic compounds. The tunnel passes under the Baltimore Harbor and carries traffic for Interstate 95, the main highway on the East Coast of the U.S. The daily traffic volume during this study was approximately 55,000 vehicles per day. Concentrations of individual compounds were determined by extracting TIGF and XAD-4 samples separately and analyzing the extracts using electron impact (EI) GC/MS for polycyclic aromatic hydrocarbons (PAHs), oxy-PAHs, alkanes and cycloalkanes in the range of C12 to C40, and hopanes/steranes. Using gas-particle partitioning theory, we estimated the saturation vapor pressure of individual SVOCs. In general, the estimated values for C12 to C40 n-alkanes agreed well with the available data. We will also present comparison of estimated vapor pressures for other compounds for which literature data is available.