Why Los Angeles has started to paint its streets white

Though it lacks the humidity of East Coast heat, Los Angeles still burns. The City of Angels is one of the only places in the United States where heat-related deaths occur regularly during winter.

This public health hazard is only expected to worsen as climate change gains strength over the next decades. Located in a desert valley and dominated by asphalt roads to facilitate its car culture, LA is extremely vulnerable – and, fortunately, innovative. The sprawling cityscape of nearly 4 million people (over 13 million in the metro area) has begun to paint its streets white, in hopes of using the color’s natural heat-reflecting properties to lower the temperature and make LA a healthier place to live.Los Angeles, and many other cities around the world, suffer from what is called the urban heat island effect, in which the dense infrastructure and activity of the city generates and traps heat beyond what might normally be expected based on the region’s climate. To combat this effect, Los Angeles is covering its streets with CoolSeal, a light-colored paint that has already yielded positive outcomes. “We found that on average the area covered in CoolSeal is 10 degrees cooler than black asphalt on the same parking lot,” said Greg Spotts, the assistant director of the Bureau of Street Services for San Fernando Valley, one of the hottest spots in Greater LA.

LA officials hope that cooler streets will result in cooler homes, which in turn keeps energy costs and health risks low. “Not everyone has the resources to use air conditioning, so there’s concern that some low-income families will suffer” if something is not done to counteract the rising heat, said Alan Barreca, an environmental science professor at the University of California at Los Angeles. “The [cool-treated] pavement would provide benefits to everyone.” The coating, which costs $40,000 per mile and lasts for seven years, will be applied to streets in a pilot program before it is applied citywide. Its future looks bright. “We’ve done things over and over again that people said couldn’t be done,” Spotts said, “and this time is no different.”