Review status: this preprint is currently under review for the journal ACP.
Rapid mass growth and enhanced light extinction of atmospheric aerosols during the heating season haze episodes in Beijing revealed by aerosol-chemistry-radiation-boundary layer interaction
Zhuohui Lin1,Yonghong Wang2,Feixue Zheng1,Ying Zhou1,Yishuo Guo1,Zemin Feng1,Chang Li1,Yusheng Zhang1,Simo Hakala2,Tommy Chan2,Chao Yan2,Kaspar R. Daellenbach2,Biwu Chu3,Lubna Dada2,Juha Kangasluoma1,2,Lei Yao2,Xiaolong Fan1,Wei Du2,Jing Cai2,Runlong Cai2,Tom V. Kokkonen2,4,Putian Zhou2,Lili Wang5,Tuukka Petäjä2,4,Federico Bianchi1,2,Veli-Matti Kerminen2,4,Yongchun Liu1,and Markku Kulmala1,2,4Zhuohui Lin et al.Zhuohui Lin1,Yonghong Wang2,Feixue Zheng1,Ying Zhou1,Yishuo Guo1,Zemin Feng1,Chang Li1,Yusheng Zhang1,Simo Hakala2,Tommy Chan2,Chao Yan2,Kaspar R. Daellenbach2,Biwu Chu3,Lubna Dada2,Juha Kangasluoma1,2,Lei Yao2,Xiaolong Fan1,Wei Du2,Jing Cai2,Runlong Cai2,Tom V. Kokkonen2,4,Putian Zhou2,Lili Wang5,Tuukka Petäjä2,4,Federico Bianchi1,2,Veli-Matti Kerminen2,4,Yongchun Liu1,and Markku Kulmala1,2,4
1Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, China
2Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Finland
3Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Beijing, China
4Joint international research Laboratory of Atmospheric and Earth SysTem sciences (JirLATEST), Nanjing University, Nanjing, China
5State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
1Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, China
2Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Finland
3Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Beijing, China
4Joint international research Laboratory of Atmospheric and Earth SysTem sciences (JirLATEST), Nanjing University, Nanjing, China
5State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
Received: 07 Mar 2020 – Accepted for review: 20 May 2020 – Discussion started: 28 May 2020
Abstract. Despite the numerous studies investigating haze formation mechanism in China, it is still puzzling that intensive haze episodes could form within hours directly following relatively clean periods. Haze has been suggested to be initiated by the variation of meteorological parameters and then to be substantially enhanced by aerosol-radiation-boundary layer feedback. However, knowledge on the detailed chemical processes and the driving factors for extensive aerosol mass accumulation during the feedback is still scarce. Here, the dependency of the aerosol number size distribution, mass concentration and chemical composition on the daytime mixing layer height (MLH) in urban Beijing is investigated. The size distribution and chemical composition-resolved dry aerosol light extinction is also explored. The results indicate that the aerosol mass concentration and fraction of nitrate increased dramatically when the MLH decreased from high to low conditions, corresponding to relatively clean and polluted conditions, respectively. Particles having their dry diameters in the size of ~ 400–700 nm, and especially particle-phase ammonium nitrate and liquid water, contributed greatly to visibility degradation during the winter haze periods. The dependency of aerosol composition on the MLH revealed that ammonium nitrate and aerosol water content increased the most during low MLH conditions, which may have further triggered enhanced formation of sulphate and organic aerosol via heterogeneous reactions. As a result, more sulphate, nitrate and water soluble organics were formed, leading to an enhanced water uptake ability and increased light extinction by the aerosols. The results of this study contribute towards a more detailed understanding of the aerosol-chemistry-radiation-boundary layer feedback that is likely to be responsible for explosive aerosol mass growth events in urban Beijing.