An analytical model (Operational Street Pollution Model - Berkowicz (1998)) has been developed to calculate pollutant concentrations in a street. The model assumes a uniform concentration distribution over the street and is therefore called "Street box" model, with the box dimensioned by the length and width of the street and the height of the surrounding built-up area. The concentration in the street is determined from a flux balance between the horizontal convective flux, the diffusive vertical flux and a continuous road transport emission source. The Prandtl-Taylor hypothesis is used to describe vertical turbulent mass transport. The model includes wind direction dependency, but does not necessarily assume re-circulation of the flow in the street canyon. The model was applied for 10 streets in the City of Antwerp, Belgium (short term simulations) and for the Podbielskistrasse in Hannover, Germany (long term simulation). The results (benzene, CO, NOx) were compared with actual measurements and with results obtained by the OSPM model. Benzene concentrations obtained in the streets of Antwerp show a reasonable agreement with measured concentrations, provided that observed vehicle numbers are used and that the correct background concentrations and meteorological conditions are taken into account by the model. (A)
Abstract