Capital Medical University - Department of Clinical Epidemiology & Tobacco Dependence Treatment Research, King’s College London - MRC-PHE Centre for Environment and Health, King’s College London - MRC-PHE Centre for Environment and Health, Huayun Sounding (Beijing) Meteorological Technology Co. Ltd, King’s College London - MRC-PHE Centre for Environment and Health, University of Leicester, Imperial College London - Department of Epidemiology and Biostatistics, Capital Medical University, King’s College London - MRC-PHE Centre for Environment and Health and Capital Medical University - Department of Respiratory and Critical Care Medicine