In 2013, The International Agency for Research on Cancer classified particulate matter (PM) as carcinogenic to humans (Loomis et al., 2013). Therefore, it is essential to measure PM concentrations to minimize the exposure of individuals. Our objective was to investigate personal exposure to PM2.5 (PM with diameter ≤ 2.5 µm) in Grenoble (France) during commuting in different transportation modes: bike, walk, bus and tramway. PM2.5 measurements were found to be the highest for bikes, followed by walk, bus, and tramway. In this study, occurring in spring at low pollution levels, exposure levels are greatly influenced by time of day. Pedestrian and cyclists' exposure generally stayed under background reference values. Exposure in public transportation was generally below reference values but when background PM2.5 levels went lower (evening), levels registered in the tramway or bus reached those of the reference. Public transport users could be less exposed than active commuters, except when ambient pollutant levels are low. Environmental parameters like wind might be important in Grenoble and it would be interesting to reproduce this study at a time when wind speed is lower.