Cyclist exposure to UFP and BC on urban routes in Antwerp, Belgium

Ultrafine particles (UFP) and black carbon (BC) concentrations show a highly dynamic micro-variability in urban area. Mobile monitoring using a bicycle platform (354 runs in 1 month) was adopted in this study to characterize the micro-variability in relation to traffic intensity, street topology and meteorological conditions. For UFP and BC a positive relationship was demonstrated between pollutant concentration and traffic intensity. In addition, the distance to the traffic and the street topology were the dominant factors influencing the UFP and BC concentrations. A high variability between streets and even within streets was observed, and also between days and hour of the day. The exposure of cyclists in urban environments is strongly linked to the spatio-temporal variability of the pollutant concentrations. Fixed-track comparisons through time revealed significant differences in exposure between days and hour of the day, but even more importantly due to the occurrence of peak concentrations along the cycling track. Peaks were mainly found near busy cross-roads and in tunnels.