Abstract
The diffusion of NO_x around Ikegami-Shinmachi crossroads was analyzed by a CFD model. This is a suspended four-lane express road with a six-lane ground-level road under the expressway and another four-lane ground-level road intersecting the two roads. The boundary conditions were given with the results from the mesoscale meteorological model. The calculations indicated high concentrations in the morning and low ones in the afternoon but did not indicate high concentrations in the evening. There still remained not negledgeble difference between the calculated results and observation.
