The Role of Grid-Based, Reactive Air Quality Modeling in Policy Analysis: Perspectives and Implications, as Drawn from a Case Study

Abstract

During the 1980s the National Acid Precipitation Assessment Program (NAPAP) supported the development of the Regional Acid Deposition Model (RADM). While sound performance evaluation was to be a part of the development process, concern existed that policy makers may hold overly optimistic expectations of RADM’s performance, and of the time to RADM’s acceptability for unrestricted use. A primary objective of this study is to gain an improved understanding of the role of quality of performance in determining a model’s acceptability and usefulness to the policy maker, and thus to aid in developing soundly-based expectations of the modeling process. The vehicle for pursuing this objective is examining the historical evolution of the Urban Airshed Model (UAM), a grid-based photochemical model that is similar in basic formulation to RADM, and its application to policy analysis in the South Coast Air Basin (SOCAB) of California.