Ronnen Levinson, who leads the Lawrence
Berkeley National Laboratory’s Heat Island
Group at the University of California, Berkeley,
said cool pavement can simultaneously
address some of the most important issues
facing the hottest cities in the U.S. and a world
experiencing alarming climate change.
“Cool pavements have potential to mitigate the
urban heat island, to save energy in buildings if
they lower the outside air temperature, reducing
the demand for air conditioning in the building,
and they can slow global warming by reflecting
more sunlight back to space,” Levinson said.
There are two basic categories of cool pavement,
Levinson said. Reflective cool pavement has
a lighter color and chemical properties that
turn sunlight back toward the atmosphere
rather than absorbing heat like dark asphalt.
Evaporative pavement relies on rainwater
seeping into its porous surface and then
cooling the pavement and the air during slow
evaporation. The choice of which technology to
use is based on whether a city gets rain during
its hottest months or is in a dry climate.
David Sailor, director of the Arizona State
Urban Climate Research Center, shared
an aerial infrared image taken from a
helicopter displaying ground temperatures in
adjoining parking lots with and without cool
pavement coating.
“The (cool pavement) surface temperature is 129
Fahrenheit,” Sailor said. “But the asphalt next to it
was at least in the 150s.”
Reducing surface temperature can have direct
benefits by lowering air temperature, which
Sailor said has “significant implications for