## 4 Results and Discussion
This is similar to the previous morphology, but with a lower building height and increased land cover (Figure 11). The buildings are freestanding, and their disposition influences the airflow direction inside the urban block. Through strategic urban planning, it is possible to create better air quality distribution in the entire area of the block. The most surfaces that correspond to air stagnation problems are at the ground floor level. Figure 12 shows good results for air quality distribution throughout the year, similar to the results from the previous example. The area between 70% and 80% on the \(x\)-axis is more prominent, which can be seen in Figure 11 where darker shades of gray are present. The main reason for this result is the disposition of the blocks and their correlation to the most frequent wind directions for the location. Figure 10: Graphical result of the quality of air in the context of air velocities higher than 0.15 m/s near surfaces of multiple-tower urban block type. Figure 9: Axonometric result of the method described in this paper on multiple-tower urban block type. N points to the north relative to the 3D model. The fifth example is a U-shaped city block. The position of the open side of the block in the context of important wind directions can give different results. The real-life urban block that was used as an input for the geometry is orientated towards two opposite directions. In this example (Figure 13), the wind flow is well balanced from all directions and the results of the analysis are good. Areas with less than 75% air distribution quality are not detected (Figure 14). The curve of the graph Is relatively smooth in contrast to our expectations. The highest number on the \(y\)-axis is around 8000; this is significantly lower than that for the multiple tower block, which is similar in volume to the U-shaped block. Figure 11: Axonometric result of the method described in this paper on slab city block type. N points to the north relative to the 3D model. Figure 12: Graphical result of the quality of air in the context of air velocities higher than 0.15 m/s near surfaces of slab city block type. Figure 13: Axonometric result of the method described in this paper on U-shaped block type. N points to the north relative to the 3D model. The sixth urban morphology is the densely populated perimeter city block. This block is typical of the urban blocks that developed from single-family housing to collective buildings in recent decades in Novi Sad. The results (Figures 15 and 16) show that most of the problems detected are inside the urban block. The graph shows that area from 70% to 80% air quality distribution is prominent, compared to most other examples. These values are representations of the area that is not suitable for window placement for natural ventilation of the building. The graph curve gradually reaches 0 between 40% and 50%, suggesting that inside of the block there are surfaces near which there is stagnant air present for most of the year. Figure 16: Graphical result of the quality of air in the context of air velocities higher than 0.15 m/s near surfaces of densely populated perimeter city block type. Figure 8:0 Graphical result of the quality of air in the context of air velocities higher than 0.15 m/s near surfaces of U-shaped urban block type. Figure 8:1 Axonometric result of the method described in this paper on densely populated perimeter city block type. N points to the north relative to the 3D model. A one-tower urban block is the seventh example of urban block geometry. The height of the building is 109 m, and the area around the object is flat. This type of block is historically usually built so natural ventilation and daylight illumination are provided for all of its inhabitants. Less than 0.7% of all surfaces have values below 95%. The results are presented in Figures 17 and 18. The graph curve is steepest for all the examples, presenting almost perfect results in regard to natural ventilation potential.