2019 Volume 54 Issue 1 Pages 28-33
Investigation of the characteristics of particulate matter suspended in a subway station platform was carried out using multiple monitoring instruments such as CPC, SMPS, APS, OPC, K-MACS (Keio-Measurement system for Aerosol Charging State), portable PM2.5 monitor, FE-SEM/EDX, and EDXRF. The PM2.5 concentrations in the subway station increased during the morning rush hour, then gradually decreased. It varied in the range of 50–120 μg/m3 showing a constant up-down pattern along with the arrival of a train in the afternoon. The PM2.5 concentrations in the subway station were approximately 2–5 times higher than those outside. In particular, particles larger than 0.5 μm were higher than those found outside. The concentrations of particulate metals such as Fe, Ti, Cr, Mn, Cu, and Zn in a subway station were several ten to hundred times higher than those outside. On the other hand, there was no significant difference in the particulate S concentrations between the subway station and the outside site. More than 70% of the particles in the subway station carried a certain amount of electric charges.
