Commutersʹ exposure to PM1 by common travel modes in Shanghai

A study on commuterʹs exposure to PM1 in Shanghai was presented. Commutersʹ real-time exposure concentrations by the common travel modes (bus, walking, cycling, taxi and subway) were measured by DustTrak™ dust monitors, and the average exposure concentrations and inhalation doses were analyzed. The lengths of the routes were designed to be within 30-min walking distance. The average PM1 exposure concentrations during commuting were 0.147 ± 0.092 mg m−3, 0.145 ± 0.088 mg m−3, 0.140 ± 0.086 mg m−3, 0.139 ± 0.086 mg m−3 and 0.122 ± 0.077 mg m−3 for the bus, walking, cycling, taxi and subway trips respectively. The concentrations in the microenvironments were 0.147 ± 0.096 mg m−3, 0.155 ± 0.098 mg m−3, 0.142 ± 0.092 mg m−3 and 0.079 ± 0.051 mg m−3 for the bus station, bus, taxi and train respectively. The concentrations in the microenvironments were close to those in Guangzhou and higher compared to the results in London, Sydney, Florence, etc. The combined effect of exposure concentration, travel time and inhalation rate led to different inter-mode relationship of inhalation doses compared to that of exposure concentrations. The inhalation doses were 54.5 ± 38.9 μg, 45.2 ± 30.1 μg, 29.2 ± 25.4 μg, 28.6 ± 25.9 μg and 12.8 ± 13.4 μg for the cycling, walking, bus, subway and taxi trips respectively. The outdoor fractions of the inhalation doses by bus, taxi and subway were much higher than the indoor fractions.