GREEN ROOFS FOR AIR POLLUTION REDUCTION: A TOOL FOR IMPROVING THE AIR QUALITY IN URBAN CONTEXTS.

Background. Regarding the environmental sustainability and Public Health scenario, cities are considered as living laboratories of Nature-Based Solutions, capable to protect and promote population health status, as well improve sustainable land use and biodiversity. Densely-built urban contexts are affected by high levels of Outdoor Air Pollution, coming from smog and fine particles, caused by vehicular traffic and combustion processes of buildings’ heating. These pollutants are the cause of several health issues and Non-Communicable Diseases such as asthma, inflammatory, degenerative, respiratory, cardiovascular and stress-related illnesses. At the same time, green areas are capable to absorb toxic substances and to filter polluted air. While the green areas in the city are fewer, green roofs are delivering excellent alternative for future implementations. Method. It has been developed a calculation model, named Green S.O.A.P. (Green Solutions for Outdoor Air Pollution), that quantifies green roofs’ capability to reduce air-pollutants, with positive benefits on environment, population health status and economic sustainability of National Healthcare System. The research work has been set into three macro-phases. The preliminary phase was a depth study aimed to identify a complete theoretical background; the proposal phase concerned the calculation model’s development; the implementation phase consisted in the application of Green S.O.A.P. in a case study identified in the city of Milano. Results. Green S.O.A.P. application, according to the percentages defined by the morpho-typological analysis of the buildings, has shown that, with the new green roofs’ construction, it’s possible to reduce the pollutants approximately up to 18,09 μg/m³ of PM10, 13,56 μg/m³ of PM2.5 and 7,24 μg/m³ of O₃ each year. Nowadays, Green S.O.A.P. is being implemented on several contexts to verify its consistency and to increase the sample of case studies. Conclusions. Green S.O.A.P. is capable to support designers, Policy Makers and planners, in order to create neighborhoods that actively contribute to improvements in population health and to plan tax incentives’ campaigns to force a positive trend into society