A NUMERICAL APPROACH STUDYING THE EFFECTS OF PRECIPITATION SCAVENGING ON STEADY-STATE DISPERSION OF AIR POLLUTANTS

Abstract

The present paper demonstrates the applicability of finite element method of weighted residuals to study the effects of precipitation scavenging through raindrops on the steady-state dispersion of air pollutants in the atmosphere under realistic variable wind and diffusivity profiles. Here, the washout of pollutants by rain droplets is considered and the whole analysis for the pollutant concentration is carried out in two phases viz. gaseous phase and droplet phase. The model solutions are obtained by using local basis and asymmetric quadratic weighting functions which can provide a promising alternative to the standard Galerkin formulation for problems with advective and diffusive terms. The results of the model reveal that the precipitation scavenging by rain is quite effective in cleaning the polluted atmosphere. Anticipating the need of pollutant concentration in rain drops regarding acid precipitation (or acid rain), the concentration of the absorbed pollutant in the droplet phase are also analyzed. So, the present study provides an understanding on the concentration distribution of pollutant in gaseous and droplet phases, under the effects of variable wind and diffusivity profiles.