American Hydrotech, Inc.,
303 E. Ohio Street, Chicago, IL 60611
Phone: 800-877-6125 Fax: 312-661-0731

Urban Heat Island Effect...

Atlanta's central business district is depicted in this photograph taken in May of 1997, at night. The temperature range indicated by the colors, from blue (coolest) to red (hottest) represents a difference of 40 degrees fahrenheit. Photo taken by NASA/EPA.

The urban heat island is a dome of higher air temperatures above a city. The urbanization of the natural landscape from forests and farmland into buildings, roadways, and other man made structures has caused average ambient air temperatures in the metropolitan areas to be anywhere from 2-12 ºF warmer than their surrounding rural areas. Heat islands occur in almost every urban center around the world and, with the exception of minor variations in geographical and climatological features, the pattern of heat islands are quite similar from city to city. Several factors are known to influence the formation of the heat islands within urban areas. The most influential being the transformation of the natural land cover from permeable soil and vegetation into relatively impermeable roadways and buildings. Natural landscapes of vegetation and soil have the ability through evapotranspiration (the loss of water from the soil both by evaporation and transpiration from the plants growing thereon) to reduce the heating potential of incoming solar radiation.  

Hydrotech's Garden Roof® will help to reduce the urban heat island effect, thereby reducing added energy demands to keep our buildings cool and reduce smog.