The characteristics of particulate matter in different subway station environmental control systems in Beijing

The characteristics of inhalable particulate matter (PM2.5, PM10) in urban subway stations can have a major impact on passengers’ health. Existing research largely fails to focus on different environmental control systems and there are few studies focused on different pollution conditions. This study therefore focused on measuring and comparing the characteristics of PM2.5 and PM10 at subway stations with three control systems in Beijing different pollution conditions. Stations including three types of control system (open, closed and screen door) and outside were monitored and analyzed using a general linear model. The concentration of PM2.5 and PM10 at different locations, such as on platforms, in carriages and in working areas, was compared and analyzed under different external pollution conditions. The results show that at different environment control systems the characteristics of PM2.5 and PM10 are different. The concentrations of particles in closed system are generally higher than screen system at platform. While the pollution in carriage is heavier for open system than that of screen system. The PM2.5/PM10 ratio was 91%, 90% and 83.84% at closed, open and screen system, respectively. While, the PM2.5 and PM10 levels inside the stations were strongly correlated with the outdoor conditions regardless of the environmental control system. This is the first study to show the PM concentration characteristics for different subway environmental control systems. As such, it provides a solid foundation for air clean studies at subway stations with different control systems.