Pollutant removal mechanism in two-dimensional street canyons: A laboratory study

Velocity and concentration fields have been measured simultaneously in the water channel to quantify the turbulent dispersion of a passive tracer emitted at street level by a line source within an idealized urban canyon. The experiment has been conducted for an arrangement of two-dimensional obstacles with aspect ratio unity. Statistical moments of velocity and concentration have been calculated with high spatial resolution. Furthermore, the simultaneous measure of velocity and concentration at the same point permitted the determination of the tracer flux in the whole domain as well as to quantify removal and re-entrainment of the pollutant through the canyon top.