Three‐dimensional analytical model of atmospheric dispersion of pollutant in a stable boundary layer

A three‐dimensional atmospheric dispersion model of a heavy admixture emitted from an elevated continuous point source is presented. Appropriate boundary conditions have been employed to model the effects of various removal mechanisms like deposition, settling and leakage of pollutants. This model takes care of variation of mixing layer height with heat flux, geostrophic drag by terrain and several meteorological parameters. A realistic form of variable eddy diffusivity is used in this model for a stable atmospheric condition. It has been found that the effect of settling of large particles is to reduce pollutant concentration always far away (horizontally as well as vertically) from the source. Whereas, in the lower part of the boundary layer near the source its effect is to increase concentration for small values of settling velocity and to decrease for larger values. The present model, being three dimensional in nature, is more suitable to assess the impact of point source emission.

Key words:

• Three‐dimensional
• atmospheric pollution
• point source
• variable eddy‐diffusivity
• variable mixing layer and net heat flux