A numerical simulation of a three-dimensional air quality model in an area under a Bangkok sky train platform using an explicit finite difference scheme

Abstract

One of the air pollution problems in areas under Bangkok sky train platforms are caused by the pollutant coming from the entrance to the tunnel. It increases the concentration of pollutant. This affects the well-being of humans and the environment. In this research, the governing equation of the air quality model in a considered area is a three-dimensional advection-diffusion equation with time dependence. A finite difference technique is employed to approximate the solution of the governing equation. This model is solved by using an explicit forward difference in time and central difference in space (FTCS). We consider the wind inflow in two cases: there is wind inflow only in x-direction and there are wind inflow in x- direction and y-direction. In addition, we added obstacles such as the columns along the middle into the tunnel. The results of the model are satisfactory. It will be able to be implemented on a problem of air pollution control in a more complicated tunnel.