VCU news

By Leila Ugincius

An urban heat island occurs when a city has significantly elevated temperatures relative to surrounding rural areas. It should come as no surprise to Richmonders that the temperature within the city is higher. But temperatures can vary even within the city itself. 

Virginia Commonwealth University’s Stephen S. Fong, Ph.D., professor of Chemical and Life Science Engineering, is a national leader in researching the effects of urban heat islands. He has led projects to map areas most affected by heat waves and to build green walls in the city, which serve multiple functions, including carbon dioxide sequestration and cooling of the local environment.

As a hot summer continues in Virginia, Fong shared with VCU News what we need to know about the urban heat island effect:

What causes the urban heat island effect? What factors contribute to it?

Urban areas basically have a double-whammy where abundance of materials like brick, concrete and asphalt absorb and retain heat leading to increased temperatures. The second half is the lack of vegetation. Plants have a cooling effect from providing shade and evaporation of water through leaves.

Why is it bad? Does it have any positive effects? 

The effect that we’ve focused on the most is the direct effect this has on health, especially heat-related illness such as heat stroke. A person’s susceptibility to heat-related illness increases with increased temperature. This may seem like common sense, but the practical aspect of it is that we might get a weather forecast saying that the high temperature in Richmond will be 95 degrees. Some areas within the city might experience temperatures below 95 degrees while others may be well over 100 degrees. We measured temperature variation around the city of 16 degrees Fahrenheit at the same time, so you can have some areas with temperatures of 90 degrees while others are experiencing temperatures of 106. We need to be aware of areas where people will be routinely experiencing elevated temperatures to warn and monitor for health impacts.

How can we reverse the effects of urban heat islands? 

There’s no single solution but possibilities range from large-scale city-driven policies to simple personal choices. At the policy level, mindful city planning that considers green spaces, building materials, and variation on building heights is important. There are also simple things that people can do including choosing colors that reflect light rather than absorb it (e.g. choosing to paint the side of a building white rather than black) and supporting efforts such as urban gardening.

What would you like to add?

Richmond has a great community of engaged citizens, nonprofit organizations, researchers and city officials with genuine interest and concern to take action on issues such as this. It is great to be part of something that translates technology and research into community action and others have recognized the importance of this issue where the Richmond Heat Island Consortium has conducted heat island studies in Baltimore, Washington, D.C., and Norfolk.