报告题目：Effects of SO2 on Organic Aerosol Formation

　　报告地点：LAPC二楼会议室

　　报告时间：2017年9月8日，上午10:00

　　报告专家：Arthur W.H. Chan教授，

　　Department of Chemical Engineering and Applied Chemistry

　　University of Toronto

　　http://www.labs.chem-eng.utoronto.ca/chan/

　　报告摘要：Ozonolysis of monoterpenes is significant source of secondary organic aerosol (SOA), a major component of particulate matter. While enhanced SOA formation has been associated with sulfate-rich conditions, the underlying mechanisms remain poorly understood. In this work, the interactions between SO2 and reactive intermediates from monoterpene ozonolysis were investigated under different humidity conditions (10% vs. 50%) in chamber experiments. Limonene SOA formation was enhanced in the presence of SO2, while no significant changes in SOA yields were observed during -pinene ozonolysis. Under dry conditions, SO2 primarily reacted with stabilized Criegee Intermediates (sCI) produced from ozonolysis, but at 50% RH, heterogeneous uptake of SO2 onto organic aerosol was found to be the dominant sink of SO2, likely owing to reactions between SO2 and organic peroxides. Organosulfates were detected and identified using electrospray ionization-ion mobility time of flight mass spectrometer (ESI-IMS-TOF). Our results demonstrate the synergistic effects between BSOA formation and SO2 oxidation through sCI chemistry and SO2 uptake onto organic aerosol and illustrate the importance of considering the chemistry of organic and sulfur-containing compounds holistically to properly account for their reactive sinks.