Computer Simulation of Pollutant Transport and Deposition Near Peace Bridge

Abstract

ABSTRACT Using computer simulations, transport, dispersion, and deposition of particulate pollutants near the Peace Bridge in the city of Buffalo, New York, are studied. An unstructured computational grid of Peace Bridge and its vicinity is generated, and the wind flow in the area is simulated. The Reynolds stress transport (RST) and the k-ϵ models of FLUENT code are used for simulating the mean airflow condition. The instantaneous turbulence fluctuating velocity is simulated by a discrete random walk (DRW) model. A Lagrangian particle-tracking model is used, and dispersion and deposition of particulate emissions from the motor vehicle exhaust on the bridge and in the Peace Bridge Plaza (customs area) are analyzed. The pollutant transport model accounts for the drag and Brownian forces acting on the particles, in addition to the gravitational sedimentation effects. For the case of a northwesterly wind of 7.7 m/s and particulate emissions in the size range of 0.01 to 50 μm, the corresponding deposition rates on various surfaces are studied. The importance of wind turbulence and gravity on particle deposition are evaluated. It is found that the Peace Bridge Plaza provides for a large fraction of the pollutants.