Numerical investigation of the effect of road structures on ambient air quality-for their better design

Two-dimensional numerical simulation for investigating wind and concentration field around a double-decked road structure was performed using a standard k– (epsilon) turbulence model. The main objective of this paper is to study how road fences installed at a double-decked road affect ambient air quality, especially, pollutant concentration at some downstream locations. For model validation, calculated results were compared with available field experiment. Performance of the standard k–(epsilon) model for the double-decked road. Obtained results clarified how and how much pollutant concentration distribution is influenced by road structures with and without fences: the fences on the upper deck have generally positive effect on decreasing of air pollution near ground level while those on the ground always not. The computer code we used is CFX4.