Better planning can reduce the urban heat island effectIn his PhD thesis, EPFL researcher Martí Bosch proposes a method for spatially quantifying the impact of mitigation measures - planting green spaces and using different building materials - on the urban heat island effect. During hot weather, cities are warmer than the surrounding rural areas. This well-known phenomenon - known as the urban heat island effect - is particularly acute at night when concrete and asphalt release the heat stored up during the day.