Phoenix is writhing.
For the past 31 days, temperatures in the desert city have reached or exceeded 110 degrees, sizzling the previous record of 18 days set in June 1974.
The historic heatwave blasted the Southwest in late June, stretching from Texas into California’s desert. But it surely’s been the town of Phoenix that is felt it the more severe.
The warmth is taxing hospitals, the town’s infrastructure, and residents’ patience.
“It’s wearing on people,” Kevin Conboy, a physician assistant with Circle the City told the Recent York Times. “Everyone’s temperatures are hovering at 100. Everyone seems to be complaining of feeling so fatigued and drained.”
But some parts of the town do not get so hot, thanks partly to a latest cool pavement technology designed to reflect the sun’s rays back into the atmosphere quite than absorb the warmth as dark asphalt does.
Town has painted over 100 miles of road with this coating material, according to the city’s website. City officials said cool pavements “had a mean surface temperature 10.5 to 12 degrees lower than traditional asphalt at noon and in the course of the afternoon hours.”
The web site also says that the nighttime air temperatures over cool pavement are half a level lower than on non-coated surfaces.
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Infrared tests reveal a difference
The Washington Post recently used infrared technology to examine if the town’s claims about cooling pavement were accurate. On one street, the typical surface temperature on asphalt was about 154 degrees Fahrenheit. The road treated with special coating had a cooler average temperature reading of 130 degrees.
“With the deployment of cool surfaces and smart technology, we are able to at the least offset a few of the urban heat effect, if not fully offset it, moving forward,” said David Hondula, director of the Office of Heat Response and Mitigation.
Phoenix is the primary U.S. city with an office dedicated to managing extreme heat.
The water-based cooling pavement treatment is 2 to 3 times costlier than the usual seal. Town eventually wants to treat 4,000 miles of residential roads.
Cooling technology at a dog park
Town pavement is not the only public space Phoenix is treating for warmth. Researchers at Arizona State University, adhesives company 3M, and the town of Phoenix are experimenting with a latest ramada in a dog park coated with Passive Daytime Radiative Cooling, or PDRC.
The fabric has higher solar reflectance and thermal emittance than typical roofs, reflecting the warmth into the atmosphere.
“What we found from initial studies were some pretty substantial positive results in terms of those coated shelters’ ability to provide a greater environment for pedestrians,” Dave Sailor, director of the School of Geographical Sciences and Urban Planning and the most important investigator on the project, told ASU News.
“It reduced what’s often called the mean radiant temperature, but in addition convected much less heat into the urban airshed, so it is a winning solution from several perspectives.”
This system has also experimented with PRDC at bus stops in the Phoenix area.
“There’s not a single blanket solution that is going to work in every single place, but by testing these design strategies, we are able to put together a portfolio of solutions that work well for providing cooling for the Phoenix metro area,” Sailor said.
He says more research continues to be needed to understand the complete profit and consequences to cool pavement.