Indoor air Quality in public facility same as bus terminal and subway station is very important for civil health. The purpose of this study was to investigate the concentration and distribution of PM10 and falling microorganism at the 5 subway stations and bus terminals from Summer 2003 to Summer 2005 in Kyunggi Province. The results were as follows. 1. The highest concentration of PM10 was $187ug/m^3$ at Bucheon Bus Terminal in 2005 while the lowest concentration of PM10 was $78ug/m^3$ at Suwon Bus Terminal in 2003. The year variation of PM10 concentration at the bus terminals in Kyunggi Province was in order of 2005 > 2004 > 2003. The average concentration of PM10 at the five Bus Terminal was $127ug/m^3$. 2. The highest concentration of PM10 was $225ug/m^3$ at Euijungbu Station l in 2004 while the lowest concentration of PM10 was $115ug/m^3$ at Suwon Station in 2003. The year variation of PM10 at the subway stations in Kyunggi Province was in order of 2004 > 2005 > 2003. The average concentration of PM10 at the five subway stations was $164ug/m^3$. 3. The average amount of falling microoganism at the five bus terminal in Kyunggi Provinc was 201CFU/plate. The minimum is 124 CFU/plate at Seongnam Bus Terminal in 2004 while the maximum is 268CFU/plate at Euijungbu Bus Terminal in summer 2005. The higher concentration of PM10 was 206CFU/plate in 2004 than 199CFU/plate in 2003 and 2005. 4. The minimum is 107CFU/plate at Anyang station in 2003 while the maximum was 263CFU/plate at Euijungbu station in 2003. The average amount of falling microoganism at the five subway stations in Kyunggi Province was 179 CFU/plate. The year variation of falling microorganism at the subway stations in Kyunggi Province was in order of 2004 > 2005 > 2003.