The Green Breath of the City: A Dynamic Approach for Air Purification through NbS in the City of Milan, Italy

Air pollution is a worldwide issue and is considered one of the biggest urban challenges and the single largest environmental health risk in Europe. Exposure to Air pollution causes serious health problems and even mortality. In recent decades, cities recognise that nature can be part of the solution to air pollution reduction. By focusing on Milan as the case study and Nature-based Solutions (NbS) as the main framework, this research aims to present the most convenient timedependent implementation strategies through a dynamic process, for maximising air purification through nature. The cycles of the city (mainly people movements) can benefit from optimizing the cycles of nature, which is here intended as a breathing system that purifies air at different rates and times of the day. Based on optimal targeting criteria, three target exposure areas have been recognized for three different timespans of the day. For the optimal selection strategy, Urban Green NbS and vegetation have been classified based on their appropriateness to different exposure time. This study aims to show that with consideration of time and locations, and by the optimal selection of Urban Green NbS and the vegetation species, air purification in all parts of the city can be maximised.