This project aims to determine the effectiveness of a number of photocatalytic materials, and in particular those incorporating titanium dioxide (TiO2) as a photocatalyst, in the reduction of urban air pollution due to the presence of nitrogen oxides (NOx).

The application of various photocatalytic materials to three types of surfaces (roadway, pavement and building frontages) in three different urban environments in the city of Alcobendas will enable monitoring of the air purification capabilities, the NOx sink effect, of the selected photocatalytic materials. The project will also examine the influence of environmental conditions (meteorology and urban configuration), changes caused by wear and the durability of these materials, as well as the optimal conditions for their implementation and maintenance. Another important aspect that will be assessed is the potential generation of by-products both in the leachates from street-cleaning and rainwater and, at atmospheric level, in the balance of gaseous pollutants and in the particulates deposited and resuspended into the atmosphere.

These real-world experiments will enable the development and optimisation of a prototype consisting of a microscale numerical model, which will process the urban atmospheric chemistry and examine the NOx sink effect of photocatalytic materials applied to various surfaces. This will enable estimation of the dispersion of gaseous pollutants in the urban areas studied and the potential impact on health.

The ultimate goal of the project is to provide local authorities with guidelines focused on viability and protocols for optimal use of photocatalytic materials with decontaminating properties, as part of an integrated assessment of urban air pollution abatement strategies.