1. Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, P. R. China
2. Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, P. R. China
3. College of Environment, Research Centre of Environmental Science, Zhejiang University of Technology, Hangzhou 310032, P. R. China
4. School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu, China
5. Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, U.K.
6. State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, P. R. China