Los Angeles Combats Heat Island Effect With Environmentally-Friendly Product

The city is looking at a pilot program that will cover a whole neighborhood

The City of Los Angeles is working on ways to reduce heat on asphalt surfaces by treating them with a revolutionary new product.

CoolSeal, which is produced by Dana Point, California asphalt protection company GuardTop, is an asphalt-emulsion sealant that can reflect enough sunlight to reduce asphalt surface temperature by as much as 30 degrees. Large roof and asphalt surfaces, according to the EPA, can trap heat and result in surface temperatures that are 50-90 degrees hotter than the air, causing what is known as the urban heat island effect. According to GuardTop, CoolSeal meets EPA and Leadership in Energy and Environmental Design (LEED) requirements of 33 percent reflectivity.


Los Angeles has been one of the first cities to experiment with CoolSeal, having recently begun a pilot program to apply the sealant to one residential block in each of its 15 Council Districts. Greg Spotts, assistant director of Los Angeles’ Bureau of Street Services, said that cool pavement coatings represent one way that the City of Los Angeles is looking to mitigate the urban heat island effect.

“We are the first city in California to test this treatment on a public road, and it has also been installed in two city facility parking lots,” he said.

“We are the first city in California to test this treatment on a public road, and it has also been installed in two city facility parking lots,”—Gregg Spotts, assistant director, Los Angeles’ Bureau of Street Services 

CoolSeal was developed for defense contractors as a means of cooling down aircraft pavement and hiding heat signatures from infrared satellites, Koleas said. He noted that, unlike most sealants, CoolSeal is a water-based asphalt emulsion, which makes it environmentally friendly.

“Other [sealants] are usually paints modified with polymers or acrylics,” said Bob Koleas, CEO of GuradTop, a California-based company founded in 1983. “Since asphalt is a byproduct of gasoline, it does not require a large carbon footprint to reproduce.”

  •  The Urban Heat Island Effect can raise temperatures on asphalt surfaces 50 – 90 degrees
  •  A new sealant can reduce asphalt surface temperatures by as much as 30 degrees
  • Los Angeles is the first city to use revolutionary asphalt sealant

The EPA maintains that elevated temperature from heat islands affects electricity consumption, emissions of pollutants and greenhouse gasses, sleep quality and even water quality. GuardTop CEO Bob Koleas estimated that Los Angeles could save $100 million per year if one out of every three streets were treated with the sealant.

Spotts said that Los Angeles also has a grant to plan a multifaceted neighborhood urban cooling project in the San Fernando Valley. He added that the city also hopes to identify funding for a second phase of the pilot in which the streets of an entire neighborhood will be covered with a cool pavement coating.

Spotts noted that, to date, officials from San Jose, San Antonio, Orlando and Dubai have contacted the city to inquire about Los Angeles’ experience using CoolSeal.

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Washington D.C. cityscape at dusk with rush hour traffic trails on I-395 highway. Washington Monument, illuminated, dominates the skyline.