SYLMAR, Calif. — Most days, Kristina Brown likes to stay out of the sun. She lives in the San Fernando Valley, where temperatures regularly hit the high 90s.

On a recent Thursday afternoon, she needed to run an errand near her house with her son, Alexander. He was shaded by a pram and they were just walking a few blocks, but Brown said even that was unusual.

“I don’t take him out in the sun really,” Brown said. “Especially because he has very fair skin, I don’t want him to get burned. We do our walks at night.”

What You Need To Know

  • The Bureau of Street Services and Streets LA are coating roads around Los Angeles with a cool pavement mixture

  • The mixture, made from sand, acrylic and a light grey coloring can reduce the temperature of asphalt by 10 degrees or more, which in turn reduces temperatures in the surrounding area 

  • New machinery has been developed to more easily coat streets with the cool pavement mixture
  • Areas that are high risk for heat related illness are being focused on first

In September, temperatures in the San Fernando Valley reached 121 degrees, a record high.

Brown grew up in the valley and while it’s an area that’s always been hot, she said she has watched the mercury rise.

“I remember running outside barefoot, you can’t do that now. The ground hurts it’s so hot,” Brown explained.

The ground, specifically the asphalt that coats roads all over Los Angeles, is making the city even hotter.

Asphalt absorbs the sun’s rays and at night releases ambient heat. The absorption increases the “heat island effect.”

Industrial areas tend to be warmer than the surrounding environment and form an “island” of high temperatures. To help combat the heat, the Los Angeles Bureau of Street Services has been working on different projects that will combat extreme heat. Since the beginning of October, they have been coating roadways around Los Angeles in a cool pavement mixture.

The mix is made of acrylic, sand, water and grey coloring. It can reduce the surface temperature of the asphalt by 10 degrees or more. Areas where temperatures are above 95 degrees are common and are being focused on first, like Sylmar in the San Fernando Valley.

Greg Spotts, chief sustainability officer for Streets LA, is overseeing the project.

“A typical black asphalt street absorbs 80 to 90% of the sun’s radiation,” Spotts said. “By putting this cool pavement coating on the street, we can reduce that to absorbing about 65 to 60% of the sun’s energy.

Absorbing less heat means the surface of the asphalt is cooler, and the area around it is cooler too.

After some practice runs, it was clear the cool pavement coating did keep streets from getting too hot, but Spotts and his team wanted to see if it was impacting the entire community, so they enlisted some help…from space.

“We partnered with NASA Jet Propulsion Laboratory,” Spotts said. “We looked at one of our projects with a thermal camera aboard the International Space Station, and we found that the parts of the neighborhood near cool pavement were on average two degrees Fahrenheit cooler.”

The Bureau of Street Services and Streets LA plan to cover 250 miles in Los Angeles with cool pavement by 2025 as part of Mayor Eric Garcetti’s Cool Streets LA Program. They are also planting trees to create more shade, particularly in neighborhoods with a low tree canopy that have historically been underserved by city resources.

“As California cities warm, the risks to heat related emergency room visits goes higher, so we need to do something to adapt the city and make it cooler,” Spotts added.

But, for Kristina Brown, and her son, it might be too late. After living in the San Fernando Valley throughout her life, Brown says, while she’s grateful the city officials are working to keep temperatures down, she’s thinking about moving.

“I want him, [Alexander] to be able to enjoy his life outside, and be able to play in the leaves and walk around in the grass,” Brown said. “It’s not the kind of environment I want my son to grow up in, it’s not the climate I want my son to grow up in.