In this study, we measured the concentration of Particulate Matter(PM10), Formaldehyde(HCHO), and Total Bacteria Count (TBC) at two facilities: day care centers, and postnatal care centers located in the cities of Gyeonggi, Gangwon, Jeolla and Gyeongsang from January 1, 2012 to December 31, 2015. PM10 concentration was similar to the day care centers and postnatal care centers. HCHO concentration was the highest in the postnatal care centers. TBC concentration was the highest in the day care centers. Comparing the different cities, PM10 concentration was the highest in Gyeonggi, HCHO concentration was the highest in Gyeonggi, and TBC concentration was the highest in Gyeonggi. As a result of HCHO's risk assessment, it was found that adults exceeded the carcinogenicity tolerance of 10−6 specified by the US EPA. This study is expected to be helpful in preventing damage to health from the contaminated indoor air at sensitive facilities, and can be used as basic data for indoor air quality management.