Comment on predictive equation published by Spanton (1983)

A method for estimating long-period pollution means, based on the Gaussian model of pollutant dispersion, has been widely applied by Warren Spring Laboratory to urban emissions of smoke and sulphur dioxide. However,.the report which is cited as the source of full model details (Spanton, 1983) contains an incorrect formulation of one of the equations, use of which results in a marked discontinuity in the profile of concentration against distance. This error is of most relevance when the model is applied to point source emissions under atmospheric conditions of high stability or high instability, although in the context of long-period mean urban pollution the error is of minor importance.