Although commuters are exposed to high air pollution concentrations, little quantitative information currently exists on differences in exposure from different modes of transport, routes, and fuel types. Teh authors measured exposures to particle number counts (PNCs) and particulate matter </= 2.5 microm in aerodynamic diameter and </= 10 microm in aerodynamic diameter (PM2.5 and PM10, respectively), on weekday mornings in diesel and electric buses, in gasoline and diesel cars, and on two bicycle routes with different traffic intensities. In addition, measurements were taken at an urban background location. Median PNC exposures were highest in diesel buses and along the high-traffic intensity bicycle route, and were lowest in electric buses. Median PM10 exposure was highest in diesel buses and lowest along the high- and low-traffic bicycle routes. Median soot exposure was highest in gasoline-fueled and diesel cars and in diesel buses and lowest along the low-traffic bicycle route. Because minute ventilation of cyclists, estimated from measured heart rates, was twice the minute ventilation of car and bus passengers, inhaled air pollution doses were highest for cyclists. Inhaled air pollution doses were lowest for electric bus passengers, except for PM10. The authors conclude that commuters' rush hour exposures were significantly influenced by mode of transport, route, and fuel type. (Author/publisher)
Samenvatting