1. Department of Pediatrics, Chonnam National University Hospital, Gwangju, Korea.
2. Department of Pediatrics, Pusan National University Children's Hospital, Yangsan, Korea.
3. Department of Pediatrics, Childhood Asthma and Atopy Center, Environmental Health Center, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
4. Department of Pediatrics, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Korea.
5. Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
6. Department of Environmental Health, Korea National Open University, Seoul, Korea.