This study was designed to verify what effect the use of a natural ventilation system can have on improving indoor air quality with regard to radon in various concentration ranges in an apartment house. The results show that both high (2~3 times higher than 148 m3) and low (similar to 148 Bq/m3) levels of indoor radon concentrations can be reduced close to and/or below the Korean IAQ guideline within 6 hours when the natural ventilation system is operated at approximately an air change rate of 0.5. In the case of an air change rate of 0.3, however, the indoor radon levels cannot meet the national guidelines and the reduction effect was insufficient with regard to various radon concentrations. Typically, the air change rate of a natural ventilation system is affected by meteorological factors such as temperature, relative humidity, wind speed, pressure. Its effectiveness varies according to such factors, for that reason, the reduction effects on radon did not increase proportionally with the ventilation time in this study.

1. 서 론
2. 연구방법
    2.1 연구대상 및 실험환경 조성
    2.2 실험조건 설정
    2.3 라돈 측정방법
3. 결 과
    3.1 대상공간에서의 실내 라돈 자연감쇄 경향
    3.2 자연환기구 부분 개방 조건에서의 라돈 변화(약 0.3 ACH)
    3.3 자연환기구 완전 개방 조건에서의 라돈 변화(0.5 ACH 이상)
4. 고 찰
5. 결 론

• 정진희(한국건설기술연구원 건축연구본부) | Jinhee Jeong (Department of Building Research, Korea Institute of Civil Engineering and Building Technology (KICT))
• 김기철(한국건설기술연구원 건축연구본부) | Kichul Kim (Department of Building Research, Korea Institute of Civil Engineering and Building Technology (KICT))
• 김지웅(한국건설기술연구원 건축연구본부) | Jiwoong Kim (Department of Building Research, Korea Institute of Civil Engineering and Building Technology (KICT) 1. 서 론 라돈(Rn-)
• 이윤규(한국건설기술연구원 건축연구본부) | Yungyu Lee (Department of Building Research, Korea Institute of Civil Engineering and Building Technology (KICT)) Corresponding author