## 4 Results and Discussion
This result is predictable considering the surrounding of the one-block building. The eighth example represents a hybrid urban block. This urban block type does not have a specific form and can have higher variety compared to previously examined blocks. The wind flow is slower in the east-west direction, as shown in Figure 8:2 North-facing surfaces and surfaces in the west are locations that have lower values of air velocity. The values are similar to results of the U-shaped block, but with more problematic areas for values under 75% air quality distribution. For those areas, the hybrid block has 1.1% of all surfaces compared to 0% for the U-shaped block. The graphical results are presented in Figure 8:3 The graph curve shows variation around 50% and 65% on the \(x\)-axis. This shows small areas with stagnant air in close proximity to the building surface. Figure 8:4 Axonometric result of the method described in this paper on one-tower urban block type. N points to the north relative to the 3D model. Figure 8:5 Graphical result of the quality of air in the context of air velocities higher than 0.15 m/s near surfaces of one-tower urban block type. The results can be seen comparatively between different urban morphologies. In Table 2, the results of all the examples are presented. It can be concluded that different morphologies produce different measurable conditions in regard to air quality with the method described in this paper. Urban blocks are modeled without surrounding blocks and trees, and thus, the maximal potential for urban blocks can be observed through this study. In cases that represent a more detailed approach, less favorable results can be expected. The highest-ranking results obtained from the tower urban block morphology, measuring 99.3% of all of its vertical surfaces, have the uppermost values for air quality distribution throughout the year. U-shaped blocks have no surfaces below 70% air quality. The lowest ranking is for the traditional urban block; the distances between buildings are short and very densely distributed. Only 54.45% of surfaces have adequate wind conditions for natural ventilation. Most of them are on the outer facades of the block. The recommendation for most inner areas is to install mechanical ventilation systems. Results for the perimeter block also show only 69% of surfaces with the highest rating. Traditional and perimeter blocks are the only ones that contain surfaces with a rating of less than 55%. Considering that the perimeter block has double the volume of the traditional block, more people living in it can be affected. Figure 8:6 Axonometric result of the method described in this paper on hybrid urban block type. N points to the north relative to the 3D model. Figure 8:7 Graphical result of the quality of air in the context of air velocities higher than 0.15 m/s near surfaces of hybrid urban block type. For comparison, the results of the static pressure from CFD simulations were exported. Low absolute values of pressure under 0.3 Pa are colored in black, and higher values, up to 11 Pa in some cases, are colored in white. The value of 0.3 Pa does not represent the threshold for experiments, but the measure for which low pressure results can easily be seen. The results are shaded according to the wind frequencies, similar to Equations (1) and (2). The results are presented with the ground plane and can be seen in Figure 8:8 Several similarities between the results of velocities and pressure levels can be observed. Bad air flow is detected in the courtyards of the first and second urban blocks. The perimeter dense block and hybrid block show results that suggest slower movement of air around them. The best results are show for the one-building block, as in Figure 8:9