Development of a magnetic hybrid filter to reduce PM10 in a subway platform

This study investigated the reduction of particulate matter (PM) in a subway platform using self-developed magnetic hybrid filters (magnet-magnet (MM) and magnet-cascade (MC) filter). The magnetic hybrid filter systems were installed and operated in Jegi-dong subway station (J station) platform. The removal efficiency of PM10 (particular matter with aerodynamic diameter less than 10 pm) was evaluated according to various influencing factors such as the combination of filters, linear velocity, and operating conditions of trains. As a result, the average removal efficiency of the MC filter (40.5%) was higher than that of the MM one (27.0%). The maximum PM10 removal efficiencies by MM (34.1%) and MC (47.2%) filters were observed at 20 (linear velocity: 2.41 m/s) and 30 jog (8 m/s) dials, respectively. We additionally found that the removal efficiency of PM10 using MM and MC filters suddenly decreased when the concentration of background PM10 in the platform increased. Based on the results of this study, hybrid technology using two or more capture principles can remove PM more efficiently than technology using a single such principle.