The heat island effect is the increased temperature observed in urban and more densely-populated and constructed areas, where the annual mean temperature may between 2 and 5.5°F higher than the surrounding area. This effect requires increased energy usage in the summer for cooling, as well as decreasing environmental quality and increasing heat-related illness and death. Pavement and roofs exposed to sunlight can heat to temperatures 50-90°F above the surrounding air, and may continue to release heat in to the air after the sun sets. More information can be found on the EPA’s website.