1. Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong SAR 999077, China
2. Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki 00014, Finland
3. Division of Environment and Sustainability, Hong Kong University of Science and Technology, Hong Kong SAR 999077, China
4. China National Environmental Monitoring Centre, Beijing 100020, China
5. Hangzhou PuYu Technology Development Co Ltd, Hangzhou 311305, Zhejiang, China
6. Air Science Group Environmental Protection Department, Hong Kong SAR 999077, China