Study of parametric effects on the SO₂ concentration in St. Louis by a numerical simulation

Abstract

An advanced urban air quality model is developed to compute temporal and three-dimensional spatial concentration distributions resulting from specified pollutant sources by numerical integration of the concentration equation. The parameterization of the model is based on improved theories of urban air pollution meteorology and turbulent transport and thus eliminates arbitrary assumptions. Urban surface roughness values are treated explicitly as input parameters. Procedures to process data of geography, source emissions, and monitoring systems are briefly discussed. The preliminary application of the model is to investigate systematically the effects of urban roughness and significant meteorological variables on the air quality distributions. The mean normalized surface concentrations are found to decrease linearly with the logarithm of surface roughness and mixing height, and to increase with wind speeds. The atmospheric stability has complex effects on the surface concentrations which have their maximum values under either neutral or extreme stable conditions. The monitoring stations can represent the averaged ambient concentrations well but not the maximum concentrations. © 1978.