The Atmospheric Physics Group of the University of Bologna has published a new study on the effects of heat island mitigation and urban pollution using Blue Nature-Based Solutions (NBS).  

The study was carried out by the I-CHANGE research team of Bologna using high-resolution and reliable numerical simulation techniques, with which a simplified city neighbourhood was reproduced. A waterbody (small lake) was virtually placed within a city neighbourhood and the thermal and dynamic process of water evaporation reproduced using a model implemented ad hoc by the research team. The effect of the presence or absence of the waterbody was evaluated, both in terms of the decrease in temperature due to the water change of phase, and in terms of the modification of the local circulation that favours the dispersion of pollutants outside the urban canopy.  

Results show the complexity of the local circulation induced by the pools of water and reveal contrasting effects: in the morning and during the day, cool waterbodies can promote widespread cooling, while in the evenings and overnight, warm waterbodies can exacerbate heat stress and environmental conditions. Hence, the benefits of the presence of water are potentially many but a careful study of local processes must be made before undertaking such structural interventions in cities.