In this study, indoor radon concentrations were measured in 56 multiple-use facilities located in Gwangju area from December 2017 to December 2018. The average indoor radon concentration in underground space was 51.70 Bq/m3, and that of the 1st floor was 38.73 Bq/m3, indicating that the indoor radon concentration of underground space was higher than that of the 1st floor. The indoor radon concentration was investigated according to the presence or absence of underground space. The concentration of radon on the 1st floor with underground space was 37.25 Bq/m3, and the concentration of radon on the ground floor without underground space was 47.94 Bq/m3. In the absence of underground space, indoor radon concentration was high. The indoor radon concentration of buildings over 30 years old was 87.26 Bq/m3, indicating a significantly higher indoor radon concentration compared to those of buildings less than 30 years old. The indoor radon concentration was investigated according to the operation of a ventilator. The indoor radon concentration of space without an operating ventilator was 52.17 Bq/m3, and that of space with a ventilator in operation for more than 8 hours per day was 36.31 Bq/m3. This result shows that the indoor radon concentration in the space with an operating ventilator is lower than the space where the ventilator is not in operation. The indoor radon concentration in the space with an operating ventilation system was lower than that on the same floor of the same building, and the indoor radon concentration of enclosed space was about 4.4 times higher than that of open space in the same building. In addition, the indoor radon concentration was measured according to the spatial features. The concentration of indoor radon of enclosed space was 64.76 Bq/m3, which is higher than those of an open space and an active space.

Abstract
 1. 서 론
 2. 연구방법
  2.1 연구대상 및 기간
  2.2 측정 및 분석방법
  2.3 통계분석
 3. 결과 및 고찰
  3.1 광주지역 다중이용시설의 실내 라돈 농도 분포 특성
  3.2 지질특성에 따른 실내 라돈 농도
  3.3 지하공간의 존재여부에 따른 실내 라돈 농도
  3.4 건축년도에 따른 실내 라돈 농도
  3.5 시설 이용 특성 따른 실내 라돈 농도
  3.6 환풍 시설 가동 및 공간의 밀폐 여부에 따른 실내 라돈 농도
  3.7 공간 특성에 따른 실내 라돈 농도
 4. 결 론
 References

• 김민진(광주광역시보건환경연구원) | Min-jin Kim (Health and Environment Research Institute of Gwangju)
• 안상수(광주광역시보건환경연구원) | Sang-su An (Health and Environment Research Institute of Gwangju)
• 조민철(광주광역시보건환경연구원) | Min-cheol Cho (Health and Environment Research Institute of Gwangju)
• 박세일(광주광역시보건환경연구원) | Se-il Park (Health and Environment Research Institute of Gwangju)
• 김종민(광주광역시보건환경연구원) | Jong-min Kim (Health and Environment Research Institute of Gwangju)
• 배석진(광주광역시보건환경연구원) | Seok-jin Bae (Health and Environment Research Institute of Gwangju)
• 조영관(광주광역시보건환경연구원) | Young-gwan Cho (Health and Environment Research Institute of Gwangju)
• 서광엽(광주광역시보건환경연구원) | Gwang-yeob Seo (Health and Environment Research Institute of Gwangju) Corresponding author