1. Department of Respiratory and Critical Care Medicine The Affiliated Hospital of Qingdao University Qingdao China
2. Department of Respiratory and Critical Care Medicine of Zhongshan Hospital Shanghai Institute of Respiratory Disease Fudan University Shanghai China
3. Department of Respiratory and Critical Care Medicine Shanghai Jing'an District Zhabei Central Hospital Shanghai China
4. Division of Environmental and Occupational Health Sciences National Jewish Health Denver Colorado USA