This study was to investigate distribution characteristics for air pollutants and to assess probability of health effect for children in kindergartens from August, 2006 to January, 2007. The mean concentrations for standards of maintenance in kindergartens were 91.5㎍/㎥ for PM10, 1,185ppm for CO2, 69.3㎍/㎥ for formaldehyde, 174CFU/㎥ for TBC and 0.41ppm for CO, respectively. For NO2, Rn, TVOC, and O3, the mean concentrations in kindergartens were 29.40ppb, 1.51pCi/ℓ, 257.3㎍/㎥, and 3.74ppb, respectively. The I/O ratio of every air pollutants exceeded \"1\" except for O3. In results of calculated safety factor to assess probability of health effect for children by air pollutants in kindergartens, safety factor for CO2 was 1.2 for fixed point. It means that children have probability of health effect caused by CO2. In cases of Monte-Carlo analysis, safety factor for PM10 was 1.0 and safety factor for CO2 was 1.2. Keywords：Safety factor, Indoor air pollution, Indoor air quality, Risk Assessment