Gaussian puff model of an urban street canyon

Abstract

A novel method has been developed to model the dispersion of vehicular pollutants in the urban street canyon environment. The method, based on the well-known Gaussian Puff Method, extends the range of applicability of earlier models in several key areas. Firstly, it is essentially a transient model which enables the user to investigate realistic situations such as traffic congestion and non-steady above canyon wind fields. In addition, it is the first model to include explicitly the effects of individual vehicles as sources of both pollutant and turbulence in the lower reaches of the street canyon. The movement of the vehicles is controlled by a simple follow-the-leader traffic model. A bespoke approach to the entrainment of puffs at roof level has also been included in the model. This paper describes the various technical details of the model and goes on to successfully demonstrate the qualitative resilience of the model by means of a short sensitivity study and a comparison with an existing model.