Effect of Nearby Road Traffic on Particulate Matter Concentrations in Subway Stations

초록

Most of subway stations are equipped ventilation units in order to replace the contaminated indoor air with fresh outdoor air. In many stations, the air intake tower is located on the ground to get fresh air from outside. However, this outdoor air is usually contaminated by nearby road traffic. In this study, the effect of road traffic on the particulate matters (PM-10) concentrations of subway stations was investigated. PM-10 concentrations at the platform, waiting room, and outdoor of 33 subway stations in Korea were analyzed by using three light-scattering counters. Each measurement was lasted for 5 minutes at each location, and the averaged value was obtained as PM-10 concentration. The amount of nearby road traffic was counted by recording the nearby road for at least 5 minutes with a camcorder. The number of passing cars was countered by reviewing the recorded images. Thus the relationships between PM-10 levels and road traffic were induced by statistical method. It was found that PM-10 levels of outdoor were proportional to the amount of road traffic. Similarly, PM-10 levels of platform and waiting room were also proportional to the road traffic. Therefore, it could be concluded that the PM-10 concentrations of subway stations are influenced by nearby road traffic. It means that the subway stations with heavy nearby road traffic need additional air cleaning unit for maintaining the good indoor air quality.