This research investigated the characteristics of CO, CO2, and NO2 concentrations at main subway stations in Busan. The annual mean CO concentrations at the Suyeong and Nampo stations were 0.75 ppm and 0.48 ppm, respectively. Annual CO2 concentration at the Seomyeon 1- platform was 649 ppm. The NO2 concentrations at the Seomyeon 2- waiting room and the Yeonsan station were 0.048 ppm and 0.037 ppm, respectively. CO concentration was highest at two times of the day, and was proportional to the number of passengers commuting to and from work. The CO and CO2 concentrations were highest in winter, but NO2 concentration was highest in spring. CO and CO2 concentrations were highest on Saturday and lowest on Sunday. The correlation of CO and NO2 concentrations measured at the subway stations with those at the ambient air quality station were highest at the Seomyeon 1 and 2- waiting room and Jeonpodong. The correlation was lowest at the Yeonsan and Yeonsandong station. The number of days when CO2 concentration exceeded 700 ppm over the last three years at the Seomyeon 1- platform was 174. The findings of this research are expected to deepen understanding of the fine particle characteristics at subway stations in Busan and be useful for developing a strategy for controlling urban indoor air quality.

This research investigated the characteristics of NO and NO2 concentration at roadside (Choryangdong) and residential (Sujeongdong) locations in Busan. The NO concentration at roadside and residential were 34.7 and 8.0 ppb, respectively, and NO2 at roadside and residential were 31.6 and 18.0 ppb ㎍/㎥ , respectively. The NO concentration was the highest in winter at roadside at 37.1 ppb, followed by 35.0 ppb and 34.0 ppb in summer and fall, respectively. NO2 concentration was the highest in spring at roadside at 39.6 ppb, followed by 30.4 ppb and 28.3 ppb in fall and winter, respectively. Number of exceedances per year of 1 hr limit value (0.10 ppm) for NO2 at roadside and residential were 3,585 and 3 hours, respectively. Number of exceedances per year of 24 hr limit value (0.06 ppm) for NO2 at roadside and residential were 32 and 1 days, respectively. Number of exceedances per year of 1 hr limit value (0.1 ppm) for O3 at roadside and residential were 1 and 14 days, respectively. These results indicated that understanding the relationship between roadside and residential could provide insight into establishing a strategy to control urban air quality.

By using hourly NO2 concentration data(1998～2000) at the Busan Metropolitan City air quality monitoring sites, characteristics of daily mean value of NO2 concentration was discussed in space and time. The correlation between NO2 concentration and other relating air pollutants was analyzed by using SAS program and meteorological parameters as well. After choosing representative 4 areas, this study used hourly concentration data(1998～2000) from air quality monitoring sites on NO2, NO, O3, CO, SO2 and PM10. Typical metropolitan characteristics of two peaks in a day was shown in the variation of NO2 concentration of Busan city.