Day-care center is one of living micro-environments for children. In urban area, day-care centers may be influencedby air pollutants emitted from the vehicle exhaust. In this work, diurnal variation of major pollutants and effectof outdoor air on indoor air quality were investigated using real-time instruments for a day-care center locatednear the heavy road. 48-h continuous monitoring at both indoor and outdoor were made in summer. The day-care center equipped with ceiling system air-conditioners was operated from 7:30 a.m. to 19:30 p.m. Indoor CO₂concentration responded greatly to the human activity. Indoor NO₂ concentration shows a big difference betweendaytime and nighttime, implying that outdoor NO₂ may penetrate into the indoor through opening of doors orwindows during the daytime. Indoor to outdoor concentration ratio of submicron particle surface area is <1 dueto the penetration of outdoor ultrafine particles.

• 김종범(한국과학기술연구원 환경복지연구단, 고려대학교 그린스쿨 에너지환경정책기술대학원) | Jong Bum Kim
• 이광재(한국과학기술연구원 환경복지연구단) | Gwangjae Lee
• 류성희(한국과학기술연구원 환경복지연구단) | Sung Hee Ryu
• 이재영(한국과학기술연구원 환경복지연구단) | Jae Young Lee
• 우성호(한국과학기술연구원 환경복지연구단) | Sung-Ho Woo
• 이승복(한국과학기술연구원 환경복지연구단, 고려대학교 그린스쿨 에너지환경정책기술대학원) | Seung-Bok Le
• 윤성택(고려대학교 그린스쿨 에너지환경정책기술대학원) | Seong-Taek Yun
• 배귀남(한국과학기술연구원 환경복지연구단, 고려대학교 그린스쿨 에너지환경정책기술대학원) | Gwi-Nam Bae Corresponding author