[1] Xi An Jiao Tong Univ, Dept Environm Sci & Engn, Xian 710049, Peoples R China
[2] Hong Kong Premium Serv & Res Lab, Kowloon, Hong Kong, Peoples R China
[3] Chinese Acad Sci, Guangzhou Inst Geochem, Changsha Ctr Mineral Resources Explorat, Changsha, Peoples R China
[4] Chinese Acad Sci, Guangzhou Inst Geochem, Guangdong Prov Key Lab Environm Protect & Resource, Guangzhou, Peoples R China
[5] Desert Res Inst, Div Atmospher Sci, Reno, NV 89512 USA