Campus News

July 19, 2010

How Emory beats heat from sprawl

How about this heat! Is there something more going on besides just being summer in the Deep South? Yes, says Jeremy Hess, assistant professor in the departments of emergency medicine and environmental and occupational health, noting that the way we design our cities is driving increased exposure to extreme heat.

Hess, who is also a consultant for the global climate change program at the Centers for Disease Control, co-authored a study with Howard Frumkin of Emory and the CDC and Brian Stone of Georgia Tech on “Urban Form and Extreme Heat Events: Are Sprawling Cities More Vulnerable to Climate Change than Compact Cities?” It’s a look at metropolitan regions, the physical layout and design of cities and the frequency of extreme heat events over five decades.

As the sprawl index the study uses shows, “Atlanta is one of the five most sprawling cities in the U.S.,” Hess says. On a regional scale, “Emory’s location inside the perimeter actually increases its proximity to the urban core, and thus its exposure to the urban heat island and associated high temperatures,” he notes. “On the micro-scale, i.e. more of a neighborhood level, the green space around the Emory campus certainly mitigates this effect to some degree.”

“Our research also suggests that sprawl is driving a greater increase in extreme heat events in the Atlanta area than in cities with more dense development. Over time, as the climate continues to warm, this could mean that Atlanta’s sprawl will further amplify extreme heat exposure,” Hess says.

Emory’s tree canopy policy — which says all trees removed must be accounted for and replaced with equal tree canopy — “mitigates against extreme heat exposure by providing shade and increasing cooling by transpiration. Trees also have a higher albedo than pavement and forested areas warm less rapidly than heavily paved ones,” Hess notes. Albedo is the ability to reflect sunlight from surfaces before it turns into heat.

Climate change will also spawn more extreme weather events, including extreme precipitation. Hess notes that “Emory’s commitment to green space helps reduce the harmful exposures from climate change in its immediate area.”

As a medical professional — Hess is also a doctor — he sees “fluctuations in certain patient complaints related to weather.” For example, more people seek medical help on smog days, for difficulty breathing, particularly related to COPD, or chronic obstructive pulmonary disease.

“Heat is associated with several different conditions,” he says, including “dehydration, renal failure, increased kidney stones.”

To fight dehydration, “Drink water early and often, at least one 8-ounce glass of water each hour on hot days,” advises Sylvia Morris, assistant professor of medicine. “Remember the majority of our bodies are water, so dehydration has effects on the entire body.”

For other defenses against the heat, the Faculty Staff Assistance Program recommends lowering the intensity of an exercise workout until you get acclimated to the heat, and exercising in early morning or evening. Also, pay attention to smog alerts and avoid afternoon exercise on orange or red alert days.

Protect yourself from the sun, advises Emory dermatologist Jamie Mackelfresh.

“There’s no such thing as a safe tan. Period,” says Mackelfresh. “A tan means skin damage.”

Re-apply sunscreen every two hours with about as much as a shot glass will hold.  Otherwise, “If you don’t reapply, it’s as if you didn’t put it on in the first place,” the dermatologist warns.

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