Ventilative Cooling and Urban Vegetation

The chapter analyses the potential usage of vegetation in cities to provide cooling effect due to plant evapotranspiration, shading and air flow control, discussing how lower temperatures, pressure differences and air flows can favour natural ventilation to improve comfort and reduce energy demand. Due to the urban heat island phenomenon, which is connected with the lack of green areas and the amount of surfaces with low albedo, cities face discomfort issues and higher energy demand for air conditioning. Urban greening, green roofs and vertical greening systems, depending on plant species, material used and climate, can improve environmental quality: at city scale mitigating urban heat island, improving outdoor comfort and providing additional benefits; at building scale, reducing the energy demand for cooling and favouring natural ventilation. In order to deeply address these aspects, the chapter comprises the analysis of case studies and monitoring activities related to urban greening, green roofs and vertical greening systems.