Adopting advanced anti-smog systems in Italy
The high concentration of contaminants in tunnels and underpasses represents a major health concern for travellers passing through these infrastructures, which moreover they tend to produce lingering hydrocarbons, which ultimately spread to the surrounding environment.
For the project for the A4 motorway extension that Salini Impregilo is carrying out in Italy, we have developed a plan to reduce pollution in an underpass located near residential areas and affected by intense traffic. The project consists in applying special photo-catalytic materials on the asphalt, and on the walls and ceilings of the underpass. These materials contain special metal compounds which when irradiated by light cause a chemical reaction that breaks down toxic substances, such as carbon monoxide, nitrogen and sulphur dioxides, benzene and particulate matter, into non-harmful ones like mineral salts and limestone.
The underpass is fitted with special UV-ray lamps to ensure the proper activation of the photo-catalytic process, which reduces the pollution from vehicle traffic to around 75-80%. In addition, as the photo-catalytic materials reflect the light up to 60% more than the traditional surfaces, we reduced the number of illumination sources used in the underpass, thereby cutting energy consumption by up to 50%.
The project is of particular relevance as it represents a useful test for materials routinely used in tunnels, and could be effectively adopted for other infrastructure projects, such as underpasses, which are very common in urban and non-urban areas.