An innovative intervention to combat the heat wave appears to be paying off in Los Angeles, where more than 600,000 square meters of dark asphalt were covered with a special reflective coating.
In a partnership between the nonprofit organization Climate Resolve and the company GAF, the coating was applied to roads, parking lots, playgrounds and basketball courts in Pacoima — one of the hottest areas in the San Fernando Valley.
The goal of the project was to limit the amount of solar radiation absorbed by the asphalt, thereby reducing heat buildup.
The results of the study, published in the scientific journal Environmental Research Communications, showed that during the severe heat wave in September 2022, afternoon air temperatures in the application area were up to 1.9°C lower compared to neighboring areas, while the temperature of the pavement surface itself dropped by about 5.5°C.
However, the scientists point out that this positive effect becomes noticeably more pronounced during extreme heat waves, while on ordinary sunny days the benefits are more limited.
Despite the encouraging evidence, the researchers make it clear that reflective pavements are not a complete solution on their own. Although they reduce the heat stored in the ground, these surfaces can reflect more radiation back to pedestrians, affecting their thermal comfort, as the sensation of heat also depends on wind, humidity and direct sunlight.
In addition, other studies examine the environmental footprint of the production and application of these materials. For this reason, experts estimate that the most effective shielding of cities against heat waves requires a combination of measures, including reflective coatings, the reinforcement of green spaces, tree planting and the creation of more shaded public spaces.
