Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration,Nanjing University of Information Science&Technology,Nanjing 210044,China;
Suzhou Environmental Monitoring Center,Suzhou 215000,China;
State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;
COVID-19; Lockdown; Satellite data; Chemical composition; Diurnal variation;