LAUSR

Abstract In this paper, we report results on commuter's exposure to particulate matter (PM). Particle number concentrations (PNC) were recorded simultaneously inside and outside the cabin of a vehicle during 45 field trips in and around Paris (France) between 2016 and 2017. For a fixed ventilation setting, the impacts of external parameters were investigated to assess commuter's exposure for a wide range of traffic conditions, including the presence of tunnels and ring road, various times during the day, the specific driving routes, different road types and vehicle speeds. Overall, our results indicate that roadway tunnels represent the worse situation for commuters resulting in the highest concentrations outside and inside the car cabin, followed by the ring road around Paris. Comparisons with a previous study undertaken in Paris and its inner and outer suburbs in 2007 reveal drastic reduction of Particle Number Concentrations (PNC) in the car cabin over this period of 10 years. More stringent emission regulations, changes in the vehicle fleet and development of low emission zones explain these promising results. Similar trends found in the recent literature for different countries corroborate the present findings.