Cities and other urban densities create heat islands, zones where summer temperatures stay higher than surrounding land. This happens because paved streets, concrete buildings, and other heat-absorbing surfaces capture and store heat. Tackling this phenomenon is a key challenge in today’s climate efforts. In the United States and in other regions, efforts are underway to introduce cooler, reflective pavements with lighter colors that absorb less heat.
A 2020 study published in Environmental Research Letters examined the use of specific coatings in two Los Angeles neighborhoods. The research showed that such coatings could lower pavement surface temperatures by as much as 10ºC.
In Pacoima, a Los Angeles area town, streets and public spaces were coated with an acrylic epoxy finishing that reflects heat. The result was a lighter blue surface compared to traditional black asphalt, which tends to trap heat. The change aims to reduce heat accumulation in the neighborhood and improve livability for residents.
Basketball court painted blue global cold cities
This reflective surface helps reflect ultraviolet rays and absorb less solar radiation, contributing to an overall drop in local temperatures.
“Pacoima is among the warmer areas in Los Angeles County. Urban heat tends to persist, so the effort to make the area more livable is a priority,” explained Jeff Terry, president of the company that led the coating project.
The blue-painted area covers ten blocks with parking facilities, a basketball court, and a training center.
Similar cooling systems have been tested in other parts of Los Angeles, including white sidewalks, with encouraging results reported by multiple studies.
multiple advantages
Backers in Pacoima are now collecting data to verify the coatings’ effectiveness in cooling the environment. Haider Taha, president and scientist of Altostratus Inc, has studied urban cooling for decades. Reducing heat in a city not only lowers energy needs but also reduces emissions from cooling systems used in homes and businesses.
Once the project covers all targeted areas, the full coating installation is expected to take five years. “We want to learn, then apply these lessons to the broader Los Angeles metropolitan area, the San Fernando Valley, and other cities and communities across the country,” said San’a, a spokesperson for the initiative. The coating materials were donated by a partner company.
Research also indicates that the cooling coating can reduce heat-related illnesses, slow fog formation in humid conditions, improve pedestrians’ comfort on sidewalks, and enhance traffic safety. Light-colored pavements reflect streetlights and headlights more effectively, making vehicles easier for drivers to see.
Lowering air temperatures in residential districts could slow certain chemical reactions in the atmosphere that contribute to smog.
Painting the streets of Los Angeles white City of Los Angeles
The coating can be applied to conventional materials such as concrete. Reflecting roughly 50 percent of sunlight, the new four-layer primary system is followed by three layers designed to reduce heat absorption from solar radiation.
Using lighter, reflective pavements is a straightforward approach to soften the heat island effect. Researchers at the Massachusetts Institute of Technology have shown that brighter roads can lower local air temperatures and reduce heatwave frequency in major U.S. cities. The strategy, however, must be applied thoughtfully; misplacement could heat nearby buildings instead of cooling them.
Also on the streets of Qatar
Los Angeles isn’t the only city exploring this idea. In Doha, Qatar, authorities launched a pilot project painting two of the capital’s main arteries blue. The test region is modest, covering two segments of about 200 meters each.
Special sensors were installed to measure how well the material lowers ambient pavement temperatures. The project is conducted in collaboration with a local company.
The study references a key MIT report and related research materials as part of its technical background.
Environment department contact: [redacted]