A system designed to control industrial emissions while protecting the environment has evolved from the Clean Air Act Amendments. The system's primary components are the pollution sources, government, economy, environment, and public influence. The functional relationship between all of the system's components manifests itself in the form of requirements for pollution permits. The pollution permits limit the environmental impact of the pollution sources while in general do not impose undue economic burdens on the sources. The environmental impact is determined by analyzing the source's pollution concentration distributions against the systems functional criteria which establish threshold limits for pollution concentrations. A computer model, a detail design component of the system, predicts ambient air concentration distributions around a proposed facility based on Gaussian Dispersion principles.

A case study of four sources in Giles County, Virginia served to illustrate the functional relationships of the system's components. A computer program, the Integrated Gaussian Model (IGM), predicted ambient air concentrations of pollutants resulting from the emissions by the four sources in the case study. The model application provided an opportunity to evaluate actual data produced by one of the system's primary detailed design components. Analysis of the results indicated that at least two of the Giles County sources in the region exceed the limits imposed by the system's criteria and thus have adverse impact on the environment.