1. Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China.
2. Preventive Medicine Department and Department of Biological Science, North China Coal Medical University, Tangshan, China.
3. Department of Civil and Environmental Engineering, Rice University, Houston, Texas.
4. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China.