DEVELOPMENT AND EVALUATION OF SBLINE, A SUITE OF MODELS FOR THE PREDICTION OF POLLUTION CONCENTRATIONS FROM VEHICLES IN URBAN AREAS

The assessment of air quality impacts from roadways is a major concern to urban planners, developers, health officials and engineers. This p aper describes the development of a suite of models, called SBLINE, fo r prediction of pollution concentrations from vehicles in urban road n etworks. The first component of the suite is ROADFAC, an emission mode l for calculating emission rates for a road link with known vehicle fl eet structure and operational details. ROADFAC can also calculate moda l emission rates, caused by deceleration, idle, acceleration and cruis e operational modes, by determining queue length and vehicle delay fro m traffic volume and signal phasing information. The other components of SBLINE are two dispersion models, called NOTLINE and CPB, for predi ction of pollution concentrations contributed by different roadlinks i n the network. These models use site geometry, meteorology, and traffi c emissions calculated by ROADFAC to predict pollutant concentrations. The contribution from a given link is calculated by using NOTLINE if that link is situated in simple topography, or CPB is run if the link is inside a canyon or a cut-section. Finally, cumulative concentration s at any receptor location are calculated by adding the contributions from all roadlinks. SBLINE can be applied to any urban network of road s, with roadlinks located in either simple topography or street canyon s. The program has been evaluated in one region of Leicester in the UK . The region represents a typical urban network of roads with some roa ds located in plain topography and some inside medium size canyons. Ob served values of pollutant concentrations an compared with predictions made from detailed measurements of the vehicle population parameters, meteorology, and local street and building topography. Well-establish ed statistical techniques have been used to show the potential of SBLI NE for application to other road networks.