The purpose of this study is to estimate the air quality of subway stations having underground platforms in Busan Metropolitan City, from September to November 2000, over seven times. The places of the investigation include Yonsan-dong station, Somyon station, Busan station, Nampo-dong station, and Dusil station.
Samplings were conducted at three points in each station, i.e. gates, ticket gates, and platforms. CO, NO, NO2, and O3 were the main components of air for this analysis. In order to more fully understand station environments, we also measured an air temperature at each point.
The results showed that the O3 average concentration of Yonsan-dong station was higher than others with 38～51ppb.
The average concentration of NO was high at the ticket gate and platform at Somyon station (119ppb, 122ppb) and Nampo-dong station (102ppb, 100ppb). These results show that the air pollution of stations with underground shopping malls were higher than others.
At Somyon station having a junction station, NO and NO2 concentration levels of platform-2 (noncrowded) were higher than platform-1 (crowded). This is most likely due to the accumulation of air pollutants and inadequate ventilation systems.
To find the relationship of the indoor (platform) and outdoor (gate), we analyzed the I/O ratio. The averages of CO and O3 were both higher than one: 1.16 and 1.82, respectively.
In the correlations between each material and the others, NO vs NO2 was the highest with R=0.63. In the correlations between indoor and outdoor, O3 was the highest with R=0.64.

• Hwa Woon Lee(Department of Atmospheric Sciences, Pusan National University) Corresponding Author
• Jong-Kil Park(School of Environmental & Science Engi., and Institute of Basic science Inje Univ.)
• Nan-Sim Jang(Department of Atmospheric Sciences, Pusan National University)
• Hee-Ryung Lee(Department of Environmental System, Pusan National University)
• Hee-Man Kim(Department of Environmental System, Pusan National University)