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article imageLos Angeles painting streets white to combat urban warming

By Karen Graham     Sep 10, 2017 in Environment
Los Angeles - Labor Day weekend brought record-breaking heat to Los Angeles, California as firefighters battled the largest wildfire the city had seen in decades. The extreme heat bears all the marks of climate change and city officials are tackling the heat head on.
There are many ways to tackle the rising temperatures brought on by global warming, many of them the result of research and new technologies. However, another way is simply using innovation - Finding new uses for products we already have available. And this is what Los Angeles is doing.
It's no secret that big cities are prone to overheating, something called the urban heat island effect. Cities are usually devoid of trees that can provide shade while there is an abundance of black asphalt, which absorbs the sun's heat. You can test this theory out yourself. Put on a black shirt on a hot day and notice how hot you become. Change to a white shirt and you will feel the difference.
In cities of more than one million people, the temperature can be more than 5.0 degrees Fahrenheit hotter than surrounding areas and sometimes even more. And as temperatures continue to rise, they will become very dangerous places during episodes of extreme heat. People will die of heat exhaustion and other heat-related injuries.
Densely populated cities tend to be warmer than surrounding areas.
Densely populated cities tend to be warmer than surrounding areas.
Heat Island Group - Lawrence Berkeley National Laboratory
Using an old idea in a new way
Los Angeles city officials looked into a product called CoolSeal, manufactured by GuardTop. The company provided a demonstration for the city's Bureau of Street Services in Chatsworth, CA. in December 2016, Engineers and department workers were shown how the mixing and application processes work and were able to witness first hand the benefits of CoolSeal compared to traditional asphalt based sealcoat.
CoolSeal is not a new idea, nor is it white. The sealant is a very light shade of gray and was originally developed for use on military air bases to keep spy planes cool while they were idling on the tarmac. This helped them avoid being detected by satellite-mounted infrared cameras, which measure heat.
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LA Street Services
GuardTop has further developed the product, and it has been tested and certified to meet the industry standard 33 percent solar reflectance design goal and is a long-lasting product. CoolSeal has done very well in pilot projects in Encino and Canoga Park, California; road temps dropped from 93 to 70 degrees in one instance, and a parking lot plummeted from 160 to 130 degrees.
The benefits of cool pavements extend beyond just cooling the local ambient air. More reflective parking lots allow building owners and cities to save on energy needed to illuminate streets and parking lots.
Los Angeles is the first city to try cooling its streets in all 15 of its electoral districts and it's part of a bigger commitment to reduce overall temperatures in the city by 3°F (around 1-2°C) over the next 20 years. The project is part of a push started three years ago where residents received a rebate if they painted their dark roofs white.
"This is an urgent challenge, and it's much bigger than one person," LA Mayor Eric Garcetti recently said. "Climate change is a fact of life that people in Los Angeles and cities around the world live with every day."
More about CoolSeal, pavement cover, Climate change, urban heat island, Innovation