Photochemical modeling of July 1994 ozone episode in the Metropolitan Seoul area

Abstract

The CIT three-dimensional Eulerian photochemical model was applied to the Metropolitan Seoul Area, Korea for July 24, 1994, a day of the 9-day ozone episode to understand the characteristics of photochemical air pollution problems in the area. The modeling domain was 60 km × 60 km with the grid size of 2 km × 2 km. As the base case emissions, air pollutant emission data of the National Institute of Environmental Research, Korea for the year of 1991 were used with modifications based on EKMA (Empirical Kinetic Modeling Approach) results. Comparisons between predicted and observed concentrations showed that the model predicted the peak concentration over the domain reasonably. It was found that the location of the peak ozone concentration was mainly decided by meteorological conditions. But the model could not resolve the spatial variations of concentration station by station, which was mainly caused by localized variations in emission and meteorology.