# Air Quality Improvement in Urban Street Canyons:
## 3 Results
### Results of Modeling Pollutant Concentrations in the Air
#### 3.3.2 Predicted Changes in Air Pollutant Concentrations in the Analyzed Street Canyons  
The annual average air concentrations of pollutants analyzed for individual street canyons and variants from the OSPM model are presented in Table 5. It contains the results of calculations of air pollutant concentrations reflecting only the impact of pollutant emissions from road transport within a given canyon (without taking into account background pollution) and the effect of this emission against the adopted background level (the same for all variants). The absolute changes in pollutant concentrations in the air for the latter case in variants v1, v2 and v3 compared to variant v0 are demonstrated in Figure 11. Furthermore, the Supplementary Materials present the results discussed above in percentage form (Figure S5) and as daily and weekly profiles (Figures S5 and S7). They visualize the predicted initial effects of implementing individual variants, taking into account the pollution background. Similarly, as was the case with changes in the volume of pollutant emissions, the greatest predicted effects of reducing the average annual concentrations in the air were obtained for variants in which passenger cars and delivery vans that did not meet a given Euro standard were banned from traffic. For example, depending on the street canyon, the expected reductions in the average annual concentrations of NO, NO\({}_{2}\), NO\({}_{\chi}\), PM\({}_{10}\) and PM\({}_{2.5}\) in the air (compared to variant v0, taking into account the background pollution) were defined at levels of approximately 16-33%, 5-9%, 11-26%, 4-9% and 3-8%, respectively, for the variants based on the Euro 4 (BROD-v2, SOLI-v3, LIMA-v1 and KRAS-v2), and approximately 23-40%, 7-12%, 16-32%, 6-14% and 4-12% for the variants based on the Euro 5 (BROD-v3, LIMA-v2 and KRAS-v3) emission standards. However, in the case of the variant in which only vehicles meeting the Euro 6 emission standard (LIMA-v3) were admitted to traffic, these reductions reached the levels of 44.5%, 13.7%, 35.8%, 14.5% and \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{3}{*}{
\begin{tabular}{c} **Street** \\ **Canyon** \\ \end{tabular} } & \multirow{3}{*}{**Variant**} & \multirow{3}{*}{**Background Status**} & \multicolumn{6}{c}{**Pollutant Concentrations in the Air [ug.m\({}^{-3}\)]**} \\ \cline{4-8}  & & & & **NO\({}_{2}\)** & \(\mathbf{NO_{\chi}}\) & \(\mathbf{PM_{10}}\) & \(\mathbf{PM_{2.5}}\) \\ \hline \multirow{3}{*}{BROD} & v0 & no & 117.2 & 30.2 & 209.8 & 48.7 & 23.7 \\  & v1 & yes & 111.8 & 29.3 & 200.7 & 44.1 & 21.6 \\  & v2 & no & 52.5 & 21.3 & 101.8 & 26.3 & 12.4 \\  & v3 & yes & 42.2 & 11.2 & 75.9 & 15.3 & 7.0 \\ \hline \multirow{3}{*}{SOLI} & v0 & no & 259.2 & 54.9 & 452.3 & 79.6 & 39.4 \\  & v1 & yes & 257.1 & 54.7 & 448.9 & 77.5 & 38.5 \\  & v2 & no & 253.7 & 54.2 & 443.3 & 72.9 & 36.5 \\  & v3 & yes & 164.5 & 41.2 & 293.5 & 44.8 & 22.2 \\ \hline \multirow{3}{*}{LIMA} & v0 & no & 522.5 & 126.2 & 927.3 & 126.5 & 68.2 \\  & v1 & yes & 251.2 & 90.1 & 475.3 & 67.5 & 34.9 \\  & v2 & no & 209.7 & 50.0 & 371.6 & 39.8 & 20.2 \\  & v3 & yes & 179.7 & 29.3 & 304.9 & 28.0 & 14.8 \\ \hline \multirow{3}{*}{KRAS} & v0 & no & 1333.6 & 334.9 & 2379.7 & 349.4 & 185.3 \\  & v1 & yes & 1367.2 & 344.9 & 2441.3 & 336.8 & 180.3 \\ \cline{1-1}  & v2 & no & 648.5 & 239.4 & 1233.8 & 188.4 & 96.7 \\ \cline{1-1}  & v3 & yes & 537.5 & 131.5 & 955.7 & 110.8 & 55.6 \\ \hline \multicolumn{3}{c}{Mean background level} & 22.4 & 30.8 & 64.6 & 38.6 & 27.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Modeling results of annually averaged air pollutant concentrations in individual street canyons for the variants considered without and with the background pollution level (mean values at the extreme points of the calculation section). 12.6%, respectively (Figure S5). They reflected the potential improvement of air quality in terms of the substances compared to variant v0.