1. State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, 100084 Beijing, P. R. China
2. Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014 Helsinki, Finland
3. Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, 100029 Beijing, P. R. China
4. Joint International research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing 210023, P. R. China
5. Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
6. State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, P. R. China
7. Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong SAR 999077, P. R. China
8. Aerodyne Research Incoporated, Billerica, Massachusetts 01821, United States
9. Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States