NOTE ON THE MEASUREMENT AND MODELING OF POLLUTANT CONCENTRATIONS ASSOCIATED WITH POINT SOURCES

This paper examines the physical concepts underlying the measurement and modeling of pollutant concentrations caused by point sources. We show that the stochastic nature of concentration fields can impose severe limitations on our ability to predict short-term concentrations. Measurements represent averages over a limited number of concentration 'events' and are thus expected to deviate from model predictions which correspond to ensemble averages. In this note we propose a method to estimate this deviation. We then illustrate the use of the technique by applying it to several cases of interest. We show that it is necessary to make an estimate of the expected deviation between predictions and observations before we can meaningfully compare them. We also briefly discuss the possible misinterpretation of model validation resulting from the use of non-dimensional concentrations. © 1979 D. Reidel Publishing Co.