Background Nitrogen oxides (NOX) are one of the main atmospheric pollutants generated by human activities, especially traffic, which accounts for around 70% of the total emissions. Through photolytic reactions this pollutant is responsible for the production of acid rain and smog, which have a very negative impact on human health. Objectives The main objective of the project is to develop the concept of ‘new anti-polluting roads’ and apply it to cities. Combined with new management structures, urban traffic control and other measures, the concept will help reduce NOX in urban areas. The technology used for eliminating NOX is heterogeneous photocatalysis using the photocatalyst, titanium dioxide (TiO2) and solar radiation. In the laboratory, this treatment has been shown to remove NOX. Specific objectives include: Submitting the system to a normalisation and standardisation process, meeting the legislative and technical requirements, ahead of its exploitation in new markets; Analysing the system from an environmental and socio-economic point of view through the data obtained in the course of the project; and Disseminating in a broad and direct way this kind of innovative system. The project also aims to demonstrate the new process in a pilot area of Madrid with a view to subsequent large-scale commercialisation. Expected results: The project expects to achieve the following results: A demonstration of the effectiveness of the system for reducing urban pollution, especially levels of NOX (by around 30-40%); The treatment of some 100 000 m2 of asphalt pavement in Madrid, leading to a 25% reduction in levels of NOX; and Transferable results that can be applied in other areas in Madrid and other cities in Europe with the same environmental problems.