<p>The current study investigates ganged stacks’ pollution dispersion parameters and their alteration trends on the ground by manipulation stack separation ratios (SR) for three stacks configuration including wind-aligned, side by side and single one. The dimensionless SR parameter is specified based on the distance between stacks divided by their internal diameter. The range of SR alterations in simulations is chosen from 1 to 18. By applying computational fluid dynamics (CFD), Reynolds-Averaged Navier–Stokes (RANS) equations along with realizable k-ε turbulence model are solved numerically. The results show good consistency with the experimental data. The critical separation ration (MCSR) as the turning point of simulations, where the maximum ground-level concentration (MGLC) shows different trends, was determined for collinear layout in value of 9 and for the cross installations was calculated 5, 10, and 11 as well. For cross designed stacks, the interaction critical ratio (ICR) was obtained 10. Also, at the worst scenario (SR = 9) MGLC point approaches to the emission sources up to 47%. According to simulations, for wind-aligned plume clouds integration, the maximum impact of the SR alteration on MGLC displacement is 4%. Further, the maximum reduction in longitudinal and transversal dimensions of the MGLC area is 25% and 46%, respectively. In order to remote MGLC from emission sources and minimize its intensity, the SR factor should be reduced as much as possible. Considering the slope of the changes after the MCSR point, the differences of longitudinal extent of MGLC area between double in-line layout and single stack is subtle. Findings offer designers helpful information to make regional plans for emergency preparedness and prevention of lands deterioration.</p>