Schoolyards as case study to implement UHI mitigation measures under a socially inclusive perspective

The UHI phenomenon is affecting cities around the world and can be mitigated through several strategies both at the macro and at micro urban scale. These mitigation measures help to assess both the UHI reduction and the improvement of users’ thermal comfort. This study is focused on the application of these strategies on schoolyards, which represent an interesting and effective site where to intervene. In Italy schoolyards are often public spaces widely distributed throughout the city and the amelioration of their microclimate conditions represent an important opportunity to improve both the children health, being children particularly sensitive to heat waves, and the social, educational and cultural values of the site. Moreover schoolyards can play an important role concerning the consciousness of the younger generation on environmental issues. A case study, consisting in three elementary schools and a middle school, located in Collegno, a town in the suburban area of Turin (north-west of Italy), was used to test the methodology to be followed in order to identify feasible solutions and assess their impact. In order to identify the critical areas inside the yards, and thus the mitigation strategies, the existing conditions were analysed through microclimate simulations performed with the software ENVI-met® v.4 Technical Preview III. The evaluations were carried out for a hot summer day, assuming as starting input the values taken from the nearest meteorological station. In parallel, due to the important social value of these spaces, a sociological investigation was carried out with the aim of identifying the solutions through a participatory process. The intervention proposals were hence simulated and results in terms of air temperatures, surface temperatures, and PET index, were compared with the values obtained for the existing conditions. Moreover simulated surface temperatures related to the existing conditions were compared with the values measured in situ with a thermal imaging camera in order to validate the results. According to the sociological analysis, the evaluated intervention strategies included the maintenance of the vegetated areas and the use of “cool” coloured coatings with high solar reflectance index for the hard surfaces like the asphalted basketball courts commonly used in the schoolyards. The simulations’ results confirmed that the climate conditions inside the schoolyards can be noticeably improved using these strategies, and in particular, they showed that the highest effect were achieved, as expected, in lowering the surface temperatures.