## 3 Results
Figure 4 shows a fairly uniform temperature distribution with a clear horizontal layer, where the average values are close to 17-17.38 \({}^{\circ}\)C. This indicates that at the initial level  
Figure 6: 3D distribution of (**a**) air velocity, (**b**) temperature, (**c**) pollutant concentration, and (**d**) combined 3D distribution of velocity, temperature, and concentration. there is a relative isotropy of the heat distribution process after stabilization. At the altitude \(z\) = 131.6 m (see Figure 4b), the average temperature is slightly lower (about 16.35 \({}^{\circ}\)C). The graph shows a more pronounced gradient than at ground level, indicating an effective vertical decrease in temperature with increasing altitude. The temperature further decreases to 13.72 \({}^{\circ}\)C (see Figure 4c). The distribution shows that the influence of the surface weakens and the inversion of layers becomes noticeable--the heat distribution is more uniform, but with a general decrease in values. At the altitude \(z\) = 500 m, Figure 4d shows the lowest temperature values are about 10.63 \({}^{\circ}\)C. Here, a clear vertical gradient is observed, typical for the atmospheric distribution, where the upper layers are significantly cooled compared to the lower ones. Figure 5 illustrates the distribution of pollution at ground level (in \(\upmu\)g/m\({}^{3}\)). According to calculations, in the final time step, the average concentration was about 0 \(\upmu\)g/m\({}^{3}\) (with maximum local values close to zero, as the pollution gradually dissipated), and the total mass of pollutant for this slice was about 140.57 \(\upmu\)g.  
Figure 5a shows a significant concentration of pollution at the initial moment, but at the final state the concentrations are reduced to zero (the average value is almost 0 \(\upmu\)g/m\({}^{3}\)), and the total mass for this section has significantly decreased. This indicates an effective dilution of the pollutant over the zone. At the height of \(z\) = 131.6 m, the concentration (see Figure 5b) also almost disappears, which confirms that the processes of dispersion and diffusion work effectively not only at ground level but also in the upper layers of the atmosphere. At the height of 263.2 m and at the height of 500 m, the concentration of pollution (Figure 5c,d) is almost zero. This indicates that even if the initial pollution was localized, as a result of dynamic processes (advection and diffusion), the substance was uniformly distributed, and its local concentration decreased to a level of almost zero. Temperature and concentration analyses and simulation parameters are presented in Tables 3 and 4. The average, maximum, and minimum temperatures change little over time. The initial data show that at \(t\) = 0, the average temperature is 14.06 \({}^{\circ}\)C, the maximum is 25.0 \({}^{\circ}\)C, and the minimum is 8.0 \({}^{\circ}\)C. As the simulation progresses, the maximum and minimum values converge to approximately 14.0 \({}^{\circ}\)C, indicating that the temperature in the computational domain is leveling off. At the start of the simulation, the concentration of pollution is quite high (average value 0.8 \(\upmu\)g/m\({}^{3}\), maximum 100 \(\upmu\)g/m\({}^{3}\)) and the total mass of the pollutant is hundreds of millions of \(\upmu\)g. However, after 15 min, a sharp decrease is observed; the average value drops to 0.06 \(\upmu\)g/m\({}^{3}\), the maximum to 3.59 \(\upmu\)g/m\({}^{3}\), and the mass decreases by an order of magnitude. Then the concentration approaches zero in all quantities. Figure 6 shows the three-dimensional distribution of air velocity, temperature, and concentration in a simulated area measuring 1000 \(\times\) 1000 \(\times\) 500 m. For each level along the \(Z\) axis (from 0 to 500 m), the average values of the parameters were calculated. At low altitude (around 0 m), lower velocities (see Figure 6a) and higher pollutant concentrations (see Figure 6c) are observed, which is explained by the proximity to the surface and ground-level pollution sources.