Measurements of roadside air pollution and traffic simulations

Abstract

Air pollution levels at the roadside were measured and trallic flows were analyzed in order to determine the dynamic features of air pollutants. Moreover, a t.raflic simulator was used to simulate observed tratTic flows and to evaluate proposed strategies. It was found that temperature-inversion above the road surface due to vehicle exhaust emissions might suppress the vertical dispersion of air pollutants in the early morning. It was also found that concentrations of air pollutants at the roadside near traffic lights had periodicity corresponding to the traffic signal cycle. But the phase of nitrogen dioxide concentration was different fkom that of suspended particulate matter. It was found that total traffic volume depended mainly on the number of small car, but level of air pollution along the roadside seemed to depend on mainly on the number of heavy-goods vehicles, A vehicle-actuated signal-control system that enables reduetion of the air pollution level at the roadside is proposed.