The report describes a method of estimating pollutant concentrations around highways which uses the Gaussian dispersion theory with empirical modification so that it more accurately represents the roadside situation. The inputs for the model have been confined to information readily available to the highway engineer namely, traffic flow, traffic speed and road layout with simple meteorological data (wind direction and speed). the pollutant concentrations can be calculated for either a single location or for a grid of receptors. The calibration and validation of the model has been based on measurements of carbon monoxide at three different locations. Methods of using the carbon monoxide value to estimate concentration of hydrocarbons, oxides of nitrogen and lead are also included. The carbon monoxide concentration derived from the model is related to a generalised distribution of pollutant concentration so that, although a single value is obtained from the dispersion model, the range of concentration likely to occur can be predicted and related to air quality criteria. (Author/publisher)
Samenvatting