Urban air pollution caused by transport, traffic congestion, and high energy use is considered one of the major challenges in megacities. This paper presents a study on the effect of using nanocoating on the buildings’ facades to improve air quality in cities. It also highlights the types and uses of nanocoating in various countries through a comparative analysis of global case studies. The objective of this work focuses on titanium dioxide as a self-cleaning photo-catalytic to mitigate pollution and improve indoor air quality. The methodology depends on inductive and analytical approaches: the first part includes a review on the nanotechnology and nanocoating, whereas the analytical part encompasses an assessment of global models for nanotechnology. The study analysed different buildings around the world that applied different types of Nanocoatings. The review of these buildings were divided according to their types of nanocoating, the country where most common types of buildings used and the country that has similar matching to Egypt’s climatic conditions. By analysing each building facades, it was helpful to extract the nanotechnologies, especially self-cleaning (photo-catalytic) that mitigate air pollution. In addition, assessments of the percentage of pollutants worldwide to identify the most important pollutants that are classified as top contaminants threatening human health, if the concentration in the internal spaces exceeds the limits recommended globally were highlighted. Finally, a review of the report of Ministry Environment, Egypt, and the maximum limits of pollutants at the global scale was also conducted, which led to the extraction of requirements to reduce contaminants in the internal spaces of buildings using titanium dioxide as self-cleaning (photo-catalytic). Results show the potential of titanium dioxide as a self-cleaning (photo-catalytic) to mitigate the level of pollution to enhance livability in cities.
