10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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The Influence of Gaseous Pollutants and Particulate Matter Concentration on New Particle Formation in Beijing
RUJING YIN, Yiqun Lu, Chao Yan, Juha Kangasluoma, Tommy Chan, Biwu Chu, Chenjuan Deng, Yueyun Fu, Xucheng He, Yiliang Liu, Xiaohui Qiao, Pekka Rantala, Yonghong Wang, Mo Xue, Gan Yang, Ying Zhou, Joni Kujansuu, Tuukka Petäjä, Yongchun Liu, Lin Wang, Jingkun Jiang, Markku Kulmala, Tsinghua University
Abstract Number: 649 Working Group: Air Quality in Megacities: from Sources to Control
Abstract In the past decades, high concentrations of particulate matter and gaseous pollutants were observed in China, especially in the most populated and industrialized regions. To improve the air quality, the government has upgraded or closed a number of unqualified enterprises and replaced coal with electricity and natural gas for residential heating in Jing-Jin-Ji region, which led to significant reductions in coal-burning-related pollutants, such as sulfur dioxide (SO2) and PM2.5.
Such changes may have profound influences on the concentration of gas-phase sulfuric acid (H2SO4). On the one hand, the source of H2SO4 was affected from two counteracting aspects: the decreased SO2 but enhanced photochemistry due to less light extinction in the clean boundary layer. On the other hand, the sink of SO2, commonly known as condensation sink (CS), also dropped significantly. The changes in H2SO4 could in turn affect new particle formation (NPF) in the atmosphere, which potentially contributes a large fraction of the number concentration of atmospheric aerosol particles. Simultaneously, the declined CS should also play an important role in regulating the occurrence of NPF.
To understand the non-linear effect of pollution reduction on the formation of H2SO4 and newly-formed particles, we conducted a field campaign at the Beijing University of Chemical Technology located in downtown Beijing. The measurement started on Jan.12, 2018. We deployed a NO3--based CI-API-TOF to measure sulfuric acid and some highly oxygenated organic molecules (HOMs) and electrical mobility spectrometers to characterize particles size distribution down to ~ 1 nm. We will present the measurement details and illustrate the effects of pollution reduction on the concentration of H2SO4 and the NPF by comparing to the data collected in 2016 and 2008 when Beijing hosted the Summer Olympic games.