The personal exposure PM10 and PM2.5 concentrations on the subway line are 1.9 and 1.8 times greater than the corresponding concentrations for the light-rail line, indicating that subway commuters are exposed to almost double the PM concentrations of light-rail commuters. In comparison to the urban ambient site (USC), PM10 and PM2.5 exposure concentrations for the subway line are on average 1.4 and 1.7 times higher, respectively; for the light-rail line, the concentrations are 0.76 and 0.94 times that of corresponding USC ambient concentrations.