Development of a Numerical Model for Pollutant Dispersion Over 3D Building Array

A CFD solver was developed by using OpenFOAM software to predict the pollutant’s dispersion over a 3D building array. A simulation mesh setup was created to replicate an actual urban environment, where the dispersion phenomena at the pedestrian level is studied. Additionally, suitable model parameters were adapted to develop a transient solver to investigate the influence of obstacle array and turbulence over a built environment. The simulation results are then compared with the published experimental data to validate the overall model sensitivity and performance by analyzing the statistical parameters. Our simulation results show good agreement at the pedestrian level of exposure with a fraction of prediction for concentration within a factor of two observation $(FC_{2})$ is 85%. Also, the model results are well agreed when analyzing the statistical parameters such as fractional bias FB, Geometric mean bias MG, Normalized mean square error NMSE and Geometric variance VG, which are 0.15, 1.17, 0.02, and 1.01 respectively. Moreover, the correlation coefficients R for horizontal concentration and velocity profiles are 0.83 and 0.91 respectively, which represent a strong model agreement. Therefore, this developed model can be used to predict the air pollution dispersion at the pedestrian level in the built environment