Ground-fixed and on-board measurements of nanoparticles in the wake of a moving vehicle

► Number concentrations of particles in the 5-560 nm size range were measured. ► Both on-board and ground-fixed sampling in the wake of a moving diesel car. ► 10 Hz sampling frequency allowed analysis of fast processes acting on nanoparticles. ► Particles entrained in the car wake differed from new freshly emitted particles. ► Complex interactions between wake and emitted plume were analysed and discussed.