10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Real-time and Off-line Applications of Oxidative Flow Reactor (OFR) for Chemical and Physical Characterization of Secondary Organic Aerosols (SOA)
YONG JIE LI, Pengfei Liu, Qi Chen, Yan Zheng, Xi Cheng, Keren Liao, Scot T. Martin, University of Macau
Abstract Number: 448 Working Group: Oxidation Flow Reactor: Development, Characterization, and Application to Aerosols
Abstract Secondary organic aerosols (SOA) are major components in atmospheric particulate organic matters. The chemical and physical properties, as well as their dynamic evolution, are crucial in our understanding of the impacts of SOA. Fundamental investigations on SOA are usually done with large-scale smog chamber facilities (SCF) or small-scale oxidative flow reactors (OFR). The flexibility of OFR makes it an attractive alternative to SCF for SOA studies. Lab-based or field-based OFR studies have offered new insights in SOA from a variety of precursors (Lambe, et al., 2011, Lambe, et al., 2012) and in different environments (Hu, et al., 2016, Palm, et al., 2018) using real-time characterization. Apart from real-time approaches, sampling of SOA after OFR for off-line analysis or processing can also be used to study different aspects of SOA properties. We will present applications of OFR for characterization of SOA using both real-time and off-line approaches. Physical and chemical characteristics of SOA from different precursors were obtained before and after exposure to gaseous ammonia to study the effects of phase state on SOA reactivity (Li, et al., 2015). A lot more characterization can be applied to SOA samples collected by either conventional filter sampling and/or thin-film formation using an electrostatic precipitator (Liu, et al., 2013). SOA collected on an attenuation total reflection (ATR) crystal aged with ammonia was investigated with Fourier transfer infrared (FTIR) spectroscopy; browning of SOA by ammonia was studied with UV-vis spectrometry (Liu, et al., 2018); evaporation kinetics and hygroscopicity were measured for the SOA film using a quartz crystal microbalance (QCM) (Liu, et al., 2016, Liu, et al., 2018). To extend these real-time and off-line applications of OFR in high-NOx conditions commonly found in urban environments, OH exposure calibration results for OFR185 and OFR254 with or without N2O injection will also be presented.
Acknowledgements This work was supported by the National Natural Science Foundation of China (grant No.: 41675120) and the Science and Technology Development Fund of Macau (grant No.: 136/2016/A3 and 016/2017/A1).
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