MITIGATING URBAN WARMING: EVALUATING THE IMPACT OF TiO2 CONCRETE TECHNOLOGY ON UHI AND UPI

Global warming is a problem that must be reviewed various perspectives, mainly through analyzing urban environments. Specifically, urban heat island (UHI) and urban pollution island (UPI) are phenomena mainly produced by natural and anthropogenic activities that contribute to this problem.
Multiple strategies have been used to mitigate this problem, including implementing photocatalytic materials on urban surfaces. Titanium dioxide (TiO2) is a transition metal oxide with photocatalytic activity, used over concrete surfaces to mitigate air pollution and reduce the air temperature in controlled laboratory conditions. Therefore, the aim of this research is to evaluate the impact of TiO2 concrete technology on UHI and UPI, specifically in NOx gases. A study case in a downtown area of Bucaramanga was studied using an ENVI-met model. In a hypothetical case, three factors were analyzed: cover ratio, location, and building height. For the analysis of UPI, the initial information for the ENVI-met model was obtained a literature review. Coverage ratios range 0%, 25%, 50%, 75%, and 100%. Furthermore, the north, south, east, and west facades were tested. Finally, the building height is between 5 to 30 floors. All the analysis was done at the pedestrian level. The results showed that the factor with the highest incidence was the height of the building. The implementation of TiO2 on the surfaces of the lower buildings showed lower temperature and NOx concentration levels at the time of analysis. Regarding the position, the technology installation was suggested on the south facade. Finally, regarding the coverage ratio, the results were indifferent NOx pollution, but it was the most influential factor on temperature. In conclusion, the implementation of TiO2 is a strategy that can decrease in average air temperature by 0.5°C, with 100% coverage in the lower building height and reduce NOx pollution levels by 5% at the pedestrian level, considering a scenario with 25% coverage, and on the south facade of lower-height buildings. These results could be implemented for the generation of public policies or for city planning to reduce the UHI and the UPI, improving the quality of life of its citizens.