Seminar

Abstract

Organic peroxy radicals (RO2) are the key reaction intermediates that determine the production of atmospheric ozone and secondary organic aerosols. However, RO2 radical has the characteristics of low concentration, strong activity, and complex reaction mechanism. The precise quantification of its ambient concentrations and the quantification of its budget is the frontier of atmospheric chemistry research. In this study, a systematic study was carried out on the direct measurement and budget analysis of the RO2 radicals in the polluted atmospheric environments in China. Based on laser-induced fluorescence technology, a RO2 radical measurement system was developed which is capable to detect the summed concentrations of all RO2 radicals as well as classification measurement of the simple and the complex RO2 radicals. Based on the chemical ionization mass spectrometry technology, we also developed a direct measurement method for the specialization detection of the complex organic peroxy radicals, and successfully realized the quantitative detection of about ten organic peroxy radicals. To interpret the measurement results of RO2 radicals, we used approaches includes box model simulations and experimental budget analysis to explore the sources and sinks of ambient RO2 radicals in the chemical complex environments. New insights about the fate and sources of RO2 are proposed for both the high and low NOx regimes.

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Professor Keding Lu is an Associate Professor at the State Key Joint Laboratory of Environmental Simulation and Pollution Control at Peking University. He received his BSc in Environmental Engineering from Nanjing University, and his PhD in Environmental Science at Peking University. He then did his postdoctoral work at the Forschungszentrum Juelich in Germany before returning to Peking University as an Assistant Professor in 2012. His research interests include spectroscopic measurement techniques and free-radical atmospheric chemistry.