1. Department of Pediatrics, Korea University College of Medicine, Seoul, Korea.
2. Department of Pediatrics, Gwangmyeong Seongae Hospital, Gwangmyeong, Korea.
3. Jungrang Elementary School, Seoul, Korea.
4. Department of Pediatrics, Sungkyunkwan University School of Medicine, Seoul, Korea.
5. Environmental Health Center for Atopic Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
6. Environmental Health Center for Childhood Asthma, Korea University Anam Hospital, Seoul, Korea.