A NOTE ON AVERAGE VERTICAL PROFILES OF VEHICULAR POLLUTANT CONCENTRATIONS IN URBAN STREET CANYONS

Recent observations of air pollutant concentrations measured within an d above street canyons were used to study the average vertical profile s of vehicular pollutant concentrations in the urban environment. The idea of an exponential vertical concentration distribution, exp(- Bz(q )), resulted from a near ground-level source diffusing over flat terra in,,was tentatively extended to the urban street canyons, where the em pirical parameters B and q are generally dependent on the atmospheric stability and the aerodynamic characteristics of the canyon.