As featured by Arizona State University News:
Summer’s heat and sun can push the surface temperature of city streets in Phoenix as high as 180 degrees Fahrenheit. Those streets then stay hot long after the sun goes down, radiating their built-up energy back into the night air, making the next morning hotter, in an ongoing cycle.
If you’ve ever owned a black vehicle, you know it gets hotter than a white or silver vehicle when parked in the sun. Scientists at the Lawrence Berkeley National Laboratory found that difference between dark and light-colored vehicles can be 10 degrees Fahrenheit or more.
The same is true for the pavement we drive on. Lighter, more reflective surfaces will stay cooler than darker ones. But could that difference be enough to make an entire neighborhood cooler and more comfortable?
Roadway engineers with the city of Phoenix put a team of Arizona State University researchers to work to answer that question. A yearlong joint study by the city and ASU applied a reflective gray treatment called CoolSeal to 36 miles of neighborhood roads and a parking lot. After months of measurements, sometimes on days as hot as 116 F, the team has some answers.
Surface temperatures of the roads with the reflective CoolSeal layer stayed cooler than non-treated streets at all times of the day; as much as 10 to 12 degrees cooler at noon, and almost two and a half degrees cooler at sunrise.
The team also took measurements of the air temperatures 6 feet above the surfaces. Here, the differences were not as dramatic. During the daytime, the CoolSeal dropped the air temperature by an average of just 0.3 degrees Fahrenheit. Nighttime temperatures improved a bit more, averaging 0.5 degrees cooler.
This article was originally posted by Arizona State University News. Read the full article here.
