This report describes the refinement of a mesoscale photochemical air quality simulation model through studies of selected chemical and meteorological phenomena that contribute to air pollution. The chemistry activities focused on the design of an automatic computer program for evaluating kinetic mechanisms, the improvement of a photochemical mechanism for incorporation in mesoscale models, and the development of a chemical mechanism for describing SO2 oxidation. The meteorology studies examined the sensitivity of the model to the inclusion of wind shear, algorithms for deriving mass-consistent wind fields, and the treatment of turbulent diffusivities and elevated inversion layers. Alternative numerical techniques for solving the advection/diffusion equation in grid models are evaluated, including various finite difference, particle-in-cell, and finite element methods, in an attempt to find a suitable methodology for accurately calculating the horizontal transport of pollutants. Finally, the report considers the problem of multiday model usage and presents results from a two-day CO simulation for the Los Angeles basin.

Includes bibliographical references (p. 283-287). "68-02-1237." "EPA 600/4-76-016 B." "May 1976." "Project Officer, Kenneth L. Demerjian." Photocopy. Research Triangle Park, N.C. : US EPA,