This report summarizes the results of a comprehensive evaluation of eight air quality models applicable to complex terrain. Seven of the models are 'Gaussian' and one is 'numerical.' The models are evaluated with data obtained from two field measurements programs. The Cinder Cone Butte data base is for tracers released upwind of a dense sampler network for a limited number of hours. The Westvaco data base contains a year of routine hourly SO2 measurements for an 11 station network. The report includes numerous tabulations of each model's performance in terms of statistical measures of performance recommended by the American Meteorological Society. The purpose of the report is two-fold. First, it serves to document for the models considered, and similar models, their relative performance. Second, it provides the basis for a peer scientific review of the models. To stay within the spirit of this latter purpose, the report is limited to a factual presentation of information and performance statistics. No attempt is made to interpret the statistics or to provide direction to the reader, lest reviewers might be biased.

Contract Number: 68-02-3514. Distributed to depository libraries in microfiche. Includes bibliographical references. "TRC Environmental Consultants."