Evaluating the cooling potential of urban greenery: an envi-met simulation case study in Italy

In recent decades, the urban heat island (UHI) phenomenon has become one of the main environmental challenges in urban areas. The intensification of temperatures in city centres, compared to surrounding rural areas, represents a concrete threat to public health, thermal comfort and urban sustainability. This paper discusses the use of the holistic three-dimensional software ENVI-met to evaluate how vegetation can mitigate UHI, focusing on a case study involving a parking lot near a supermarket in a municipality in the centre of Italy. It details the simulation process, including the selection of appropriate tree species, and two different arrangements within the parking area to enhance cooling effects. Simulations were carried out starting at 6:00 am for a duration of 24 hours, with the aim of evaluating the potential air temperature at 2:00 pm and the PMV and PPD comfort indices for the statistically representative summer and winter day; a comparison with the state-of-the-art with no greenery was then performed. The study emphasizes the importance of creating realistic models to assess temperature and comfort indices effectively. Results indicate that strategic planting can significantly lower temperatures and improve comfort levels in urban settings; it can be stated that the most suitable tree for the creation of a green parking lot is the Acer Campestre, thanks to its ability to lower the temperature by approximately 1.5°C and improve comfort indices; moreover, it is shown that the optimal arrangement of trees can significantly influence the microclimatic conditions of the parking lot.