Why L.A. is
coating its streets with material that hides planes from spy satellites
Climate
change conjures up distant images of rising seas and cracking ice sheets, but
in cities across the United States the effects of global warming are
apparent as soon as you step outside.
It’s known as the “urban heat island effect,” and it
refers to the pockets of intense heat captured by the concrete, asphalt, dark
roofs and the dearth of foliage that define many American cityscapes.
Los Angeles — surrounded by desert and encased in thousands of
miles of asphalt — is the poster child of the heat island effect, experts say,
which explains why city officials are exploring innovative ways to combat
record-breaking, rising temperatures. Los Angeles Mayor Eric Garcetti wants to
reduce the city’s average temperature by 3 degrees Fahrenheit over
the next 20 years, according to the Los Angeles Times.
One
tactic for achieving that goal may involve coating city streets in a substance
known as CoolSeal, a gray-colored coating designed to reflect solar
rays. City officials said CoolSeal has already shown promising results.
The coating was first tested in 2015 on a parking lot in the San Fernando
Valley, one of the hottest parts of town, according to Greg Spotts, the
assistant director of the Bureau of Street Services, which oversaw the testing.
Summer temperatures in the area — which average in the upper 80s — have climbed
above 100 degrees multiple times over the past year.
“We
found that on average the area covered in CoolSeal is 10 degrees cooler than
black asphalt on the same parking lot,” Spotts said. “We thought it was really
interesting. It’s almost like treated asphalt warms at a lower rate.”
City officials claim Los Angeles is the first
U.S. city to test cool pavement to fight urban heat.
The hope, they say, is that cooler streets will lead to cooler
neighborhoods, less air conditioning use and fewer heat-related deaths. The
metropolis is one of the only cities in the nation that experiences
heat-related deaths in the winter, a phenomenon expected to worsen alongside
temperatures, Spotts said. Complicating matters, experts say, is the fact that
many Los Angelinos live in multifamily dwellings without air conditioning.
“Not everyone has the resources to use air conditioning, so
there’s concern that some low-income families will suffer,” Alan
Barreca, an environmental science professor at the University of California at
Los Angeles, told Agence France-Presse. “That bothers me on
a moral dimension. The pavement would provide benefits to everyone.
“It can protect
people who have to be outdoors,” he added.
Officials
believe treated streets are more comfortable for pets as well, as Fox affiliate
KTTV found when they tested whether pets
that avoided hot asphalt were more willing to walk on a treated roadway.
To
determine whether CoolSeal is cost-effective and how it influences drivers,
Spotts said his agency has applied the product to designated streets in 14 of
the city’s 15 council districts, where it will be monitored and studied through
the fall.
“We
think that more than 10 percent of the city is asphalt — that’s 69,000 city
blocks,” Spotts said. “There’s been estimates that suggest covering a third in
the city’s pavement with a cooler materials might be able to move the needle on
the city’s temperature.
“We’re
not ready to do that, but we do want to explore what it might take to go big
and take this thing to scale,” he added.
The
coating costs about $40,000 per mile and lasts seven years, officials said.
Street Services is carrying out their pilot program with
GuardTop, a California-based, asphalt coating manufacturer. The company began
working with the defense industry to develop cool pavement for military spy
planes, according to Jeff Luzar, GuardTop’s vice president of sales.
Luzar
said the officials were interested in lowering the temperature of taxiways so that
aircraft would be less easily seen by spy satellites using infrared cameras,
which form images using thermal energy. Years later, the product being applied
to Los Angeles streets is similar, but it has been refined over the years to
make it even more solar reflective.
Since
news about the pilot program broke, GuardTop has received inquiries from all
over the world, including China, Israel, Australia and Saudi Arabia.
Spotts
said the attention the pilot program has received shows Los Angeles is ahead of
the curve when it comes to combating global warming. The city began using
natural gas-fueled trash trucks and commuter buses ahead of other cities, he
said.
“We’ve done things over and over again that
people said couldn’t be done, and this time is no different,” he said.
By Peter Holley
https://www.washingtonpost.com/news/innovations/wp/2017/08/18/why-l-a-is-coating-its-streets-with-material-that-hides-planes-from-spy-satellites/?utm_term=.9806527a9801&wpisrc=nl_innov&wpmm=1
No comments:
Post a Comment