This paper describes the procedures followed in developing and validating computer models of air pollution caused by airports. Such dispersion models are used to calculate how the pollution emitted from the many contributing sources spreads to affect surrounding areas. This simulation permits a realistic evaluation of possible alternative strategies for air pollution abatement.The basic elements of a modeling problem are seen to be the emission sources, the meteorology, and the dispersion parameters; current methods for handling each of these are explained. The treatment of a sample airport is described, and typical results are presented. Finally, the paper indicates some of the areas in which limited knowledge affects the implementation or accuracy of airport dispersion modeling.