1. School of Environment, Tsinghua University, Beijing 100084, P. R. China
2. State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 10084, P. R. China
3. State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
4. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, P. R. China
5. School of Advanced International Studies, Johns Hopkins University, Washington, DC 20036, United States
6. Business School, Beijing Normal University, Beijing 100875, P. R. China
7. School of International and Public Affairs, Shanghai Jiao Tong University, Shanghai 200030, P. R. China
8. State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, P. R. China