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Cool Roads Combat City Heat: A California Test
25 Jul
Summary
- Solar-reflective coating reduced road surface temperatures by up to 5°C.
- Air temperature near the ground fell by about 0.2°C during midday and evening.
- Coating's cooling ability declined by 30% after one year due to aging.
Urban centers are seeking solutions for escalating temperatures, and a California experiment suggests that cool pavements could play a role. A peer-reviewed study found that applying a solar-reflective coating to roads reduced surface temperatures by as much as 5°C, although adjacent air temperatures only dropped by approximately 0.2°C.
These cool pavements increase their ability to reflect solar radiation, unlike traditional dark asphalt which absorbs more heat. While the California test demonstrated reduced afternoon and morning surface temperatures, researchers noted that traffic and pollution caused the coating's reflective properties to degrade by 30% within a year.
Despite the promising initial results, the study cautions that cool pavements are not a sole solution for urban overheating. The reflective surfaces may also bounce more sunlight onto surrounding areas. Further research is needed to fully understand their impact on human thermal comfort, and they should complement other heat mitigation strategies like planting trees and increasing green spaces.
