Personal exposure to PM2.5 during commuting in Shanghai

The impact of microenvironment on public health has received increasing attention, especially in the traffic and living microenvironment. This study shows a comparative research of PM_2.5 exposure concentrations associated with five commuting modes (i.e., walking, bicycling, car, bus and subway) in haze and non-haze periods in Shanghai, China. On the days of observation, the experimenter carried portable instruments to measure personal PM_2.5 exposure concentrations, commuting by different transport modes, following designated routes round Century Park in Shanghai. Fixed observations of indoor and background concentrations of PM_2.5 were also taken for comparison in a three-story building nearby. We found that the choice of different commuting modes will result in different personal PM_2.5 exposure levels. During the haze periods in winter, cyclists followed by pedestrians had the highest PM_2.5 exposure than those who commuted by subway, bus and car with controlled ventilation settings. During the non-haze periods, subway commuters had the highest PM_2.5 exposure. By contrast with personal exposure, the hourly inhaled dose of PM_2.5 was higher among active commuters than among commuters who used motorised transport such as subway, bus and car. Our results may provide information to help develop exposure mitigation strategies for public health protection.