报告题目：Understanding organic aerosol formation and heterogeneous degradation through laboratory studies

报告人：Dr. John Liggio / Senior Research Scientist   

工作单位：Environment Canada

报告摘要：Over the last several decades, significant progress has been made in understanding both secondary organic aerosol (SOA) formation and heterogeneous degradation processes. Traditionally, such advances in knowledge have occurred through the use of large volume environmental chambers, which have been able to simulate atmospheric processes on the time scale of minutes to hours. However, technical issues have limited the use of such chambers in the systematic investigation of multiple SOA precursors, over long atmospheric time scales (days) including their heterogeneous loss mechanisms. In the current presentation, a new OFR is described, characterized and used to study organic aerosol formation, chemistry and heterogeneous oxidative aging from two important industrial/commercial emission sources: petrochemical facilities and flame retardant usage. The OFR approach was applied to petrochemical-related precursor mixtures from the Canadian Oil Sands (OS) (a large source of hydrocarbon emissions), to improve our understanding of SOA yields from this source, the impact of precursor volatility on the yields, and the effect of other atmospheric conditions such as NO_x and OH radical exposure on SOA composition. In addition, the OFR was applied to the study of particulate organophosphate flame retardants (OPFRs), which are ubiquitous in the global atmosphere, and whose environmental impacts have not been adequately assessed due to a lack of data associated with their atmospheric heterogeneous transformations. The importance of such transformations for OPFRs are explored by investigating the reaction kinetics, degradation chemical mechanisms and toxicological evolution of two OPFRs (2-ethylhexyl diphenyl phosphate (EHDP) and diphenyl phosphate (DPhP)) coated on (NH₄)₂SO₄ particles upon heterogeneous OH oxidation. Using recently developed real-time particle chemical composition measurements, particulate products from heterogeneous photooxidation and the associated degradation mechanisms for particulate OPFRs are determined for the first time.

报告人简介：John Liggio received his B. Sc. and Ph.D degree from York University, Canada, in 1999 and 2004, respectively. He has been the PI and the research scientist at Environment Canada since 2008. He is doing researches on arctic marine VOC emissions, arctic secondary organic aerosol processes, organic aerosol evolution from urban and industrial sources, vehicle emission characterization, biogenic aerosol formation and evolution, heterogeneous reactions of organic aerosols, laboratory studies of VOC and SVOC uptake to acidic aerosols and associated kinetics, industrial nanoparticles and human toxicity and chemical ionization mass spectrometry measurements of gases and aerosols. He has published more than 70 papers in high level of journals such as Nature, Nature Comm., Proc. Natl. Acad. Sci.USA, and Environ. Sci. Technol.etc

报告时间：2019年11月4日14:30-16:00

报告地点：科学会堂二楼会议室