1. Department of Occupational and Environmental Health, School of Public Health, Xi'an Jiaotong University Health Science Center , 76 Yanta West Road, Yanta District, Xi'an, Shaanxi 710061 , China
2. Key Laboratory of Trace Elements and Endemic Diseases in Ministry of Health , Xi'an, Shaanxi 710061 , China
3. Key Laboratory for Disease Prevention and Control and Health Promotion of Shaanxi Province , Xi'an, Shaanxi 710061 , China
4. Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University , 38 Xueyuan Road, Haidian District, Beijing 100191 , China
5. Yunyi Health Technology Co. Ltd. , Tianfu Street, Daxing District, Beijing 102629 , China
6. Medical Apparatus and Instrument Commitee, China-Europe Association for Technical and Economic Cooperation , No.17 Houshayu section, Shunyi District, Beijing 101318 , China
7. Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University , 722 West 168th Street, New York, NY 10032 , USA