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ASU researchers helping Tempe deal with extreme-heat events

Projects are investigating urban planning, shade to mitigate heat for pedestrians

July 19, 2018

It’s predicted to be 116 degrees in Tempe on Tuesday. Scorching.

That kind of extreme heat is a dangerous annual stress on city resources. Last year, the Tempe Fire Department responded to 141 calls for heat-related emergencies. There have been 84 heat-emergency calls so far this year.

So, Arizona State University researchers are working with the city of Tempe on ways to mitigate the effects on the people who live here. A teamCoseo, Middel and Hondula all are senior sustainability scientists in the Julie Ann Wrigley Global Institute of Sustainability. from the Urban Climate Research Center has several projects happening now, which the city discussed in a press conference on Wednesday.

Paul Coseo, an assistant professor of landscape architecture in the Herberger Institute for Design and the Arts, researches urban climate design, which is the idea that cities should be designed more intentionally.

Paul Coseo, an assistant professor of landscape architecture, is working on a project with the city of Tempe to holistically address weather extremes. Photo by Charlie Leight/ASU Now

“I focus on issues here with the urban heat island and the problem we have with the way cities are built,” he said. “Typically we’ve used way too much concrete and that makes our cities hotter.”

He said the answer is a variety of strategies, such as building taller buildings to create more shade or even narrowing the width of traffic lanes to remove concrete and asphalt.

“It’s not just planting trees or converting concrete to native desert. It’s about holistically thinking about the way we build our cities and for me that’s a design question,” he said.

Coseo, who teaches in the Design School, has a grant from the National Science Foundation to look at weather extremes at both ends — by working with Tempe and the city of Buffalo, New York; Erie County and the University of Buffalo. His project will look at how government entities deal with weather, such as whether different departments work together and how policy is implemented.

So are any mitigations the same for both extreme cold and extreme heat?

“That’s the tricky thing — we don’t have enough research,” he said. “We have a lot more on how the way we build our cities affects extreme heat. We don’t have enough on the cold side.

“People in Buffalo have thought, ‘It’s just cold. What can we do?’"

Ariane Middel, an assistant professor in the School of Arts, Media and Engineering in the Herberger Institute for Design and the Arts, also is working with the city of Tempe on how shade mitigates heat.

“Air temperature does not vary a lot but what varies is how we experience those temperatures and this experience is mainly driven by shade,” she said.

People can feel that it’s 20 to 30 degrees cooler in the shade even though the air temperature is not that different.

Ariane Middel, an assistant professor in the School of Arts, Media and Engineering, has designed a mobile weather station to measure how pedestrians experience heat. Photo by Charlie Leight/ASU Now

Middel has built a mobile weather station that she calls “Marty,” for MRT — mean radial temperature. Marty measures the total radiation that hits the body outdoors, including sunlight and the heat emitted from surfaces like asphalt.

She’s using Marty to measure the benefits of shade at the Rio Salado Arts Park, next to the Tempe Center for the Arts, where the city planted trees a few months ago.

“We’ll be monitoring over the next 10 years to see how the shade benefit increases and also to see how park use increases,” she said.

Middel also is working on a project she calls “50 Grades of Shade,” measuring the efficiency of different types of shade including trees, awnings and buildings.

The results of her studies will help Tempe figure out how pedestrians experience heat at street level.

“Then that will be used to route people along the most comfortable path,” she said.

David Hondula, assistant professor in the School of Geographical Sciences and Urban Planning, said that Tempe is a leader in using statistics and research in setting policy to deal with the heat.

“The statistics allow us to dispel myths,” he said. “Forty percent of heat-related deaths have an indoor place of injury. It’s hot outside for all of us and it’s hot inside for many of us.”

He also said that many people think most heat victims are visitors unaccustomed to the climate, but the vast majority are people who have lived in Arizona for many years.

“2016 and 2017 were certainly warm years but the evidence leads us to believe that changes in social-service programs might be responsible for increasing vulnerability,” he said of the countywide death rate.

“We saw an unfortunate increase in the number of unsheltered homeless people in our community between 2015 and 2016, and a corresponding increase in the share of heat-related deaths.”

Tempe Mayor Mark Mitchell said that ASU has run workshops on dealing with extreme weather events for city staff and has connected Tempe with other cities and universities to address the issue.

“Tempe is taking the threat of climate change seriously and we are planning accordingly,” he said.

Stay safe in the heat

The city of Tempe, Maricopa County and Arizona State University researchers provided these tips to stay safe in extreme heat:

• Check on your neighbors. Heat-related illness disproportionately affects older people so make sure elderly people are OK.

• When the temperature is in the high 90s or higher, indoor fans won’t prevent heat-related illness. Stay in an air-conditioned space.

• Never leave children or pets in a vehicle when it’s hot. A recent ASU study found that a car can hit 116 degrees inside after one hour parked in 100-degree temperatures.

• Drink water all day long. Skip sodas or sugary or alcoholic drinks because water is the best hydrator. 

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