The concern of fine particle (PM2.5) management of outdoor environments has been increasing due to its exposure and related health effects in Korea. As a result, PM2.5 standard in atmosphere environment was regulated in 2015. On the other hand, indoor PM2.5 standard has been required because most people spent their times in indoor environments. In this study, we measured the PM2.5 and PM10 concentrations both indoor and outdoor environments of public-use facilities such as underground stations, underground shopping centers, and nurseries for 24 hour with filter-weighing method in Seoul and Daegu. Measurement duration was from March to April in 2014 during the Asian dust period. At all measurements, indoor to outdoor (I/O) concentration ratios exceeded 1 except 1 day nursery in Daegu in spite of Asian dust period. The ratios of PM2.5 to PM10 concentrations ranged from 0.63 to 0.75 in indoor environments, and from 0.63 to 0.82 in outdoor, indicating that PM2.5 should be carefully managed in indoor environments as well as outdoor atmosphere. Keywords : PM2.5, PM10, Public-use facilities, Indoor environments