1 School of Public Health, Capital Medical University, Beijing, People's Republic of China.
2 Department of Allergy, Beijing TongRen Hospital, Capital Medical University, Beijing, P. R. China.
3 Beijing Laboratory of Allergic Diseases, Beijing Municipal Education Commission, Beijing, P. R. China.
4 Laboratory for Environmental Health and Allergic Nasal Diseases, Laboratory for Clinical Medicine, Capital Medical University, Beijing, P. R. China.
5 Department of Occupational and Environmental Health, Fourth Military Medical University, Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, Xi'an, P. R. China.