Abstract
In order to clarify the mechanism o f photochemical smog in the Tokyo Metropolitan Area, numerical simulation was performed. First, only dispersion was treated, by the use of sulfur dioxide (SO2) and nitrogen oxides (NOx) as inert gas. And then photochemical smog was simulated by the dispersion model thus evaluated, combined with a photochemical reaction model.
The simulatio n model was developed in both Lagrangian and Eulerian forms, and case studies were carried out. In the Lagrangian approach (namely, moving parcel method), lateral diffusion was considered by "receptor-oriented method" and Friedlander and Seinfeld (1969) was used as a photochemical reaction model. In the Eulerian approach, calculation scheme MRI-E10 was developed for preventing "artificial diffusion" (see Appendix A), and the reaction model by Eschenroeder and Martinez (1971) and Sugiyama (1974) was utilized.
Generally speaking, results for SO2 and NOx were fairly good. Simulation of the photochemical smog, however, was not so satisfactory yet. More information on the emission source (especially of hydrocarbon) in the area is indispensable, and a more practical model of the photochemical reaction in the atmosphere should be developed.
