Wind tunnel experiments on micro-scale dispersion of exhausts from motorways

Since exhaust gases from road traffic are mainly released in the immediate vicinity of urban areas, constructive measures are required to prevent unfavourable immissions. Up to now, the micro-scale dispersion of exhausts could not be sufficiently predicted by purely theoretical methods. At the Ruhr-University Bochum, wind tunnel experiments have been conducted. Aerodynamic similarity criteria for the atmospheric boundary layer and in particular the traffic-induced turbulence have to be considered. Comparison of time averaged concentrations, measured in situ and in the corresponding wind tunnel model, prove the reliability of this experimental tool. With this background, the influence of different noise abatement barriers on the spread of exhaust gases is systematically investigated.