A couple of years ago, we shared an article about how Los Angeles was painting certain asphalt roads with a light, paint-like material made by CoolSeal. Their hope was that it would reduce heat island effect in the warmest part of their city. A recent study has found that the coating may not actually have the effect that the city was hoping for.
According to CityLab, who received an advanced copy of the report to be published by the American Meteorological Society, a person walking down a street coated by the CoolSense product could actually be feeling temperatures up to 7 degrees warmer than typical asphalt pavement.
Whereas asphalt will absorb the heat from the sun, the coating reflects it back immediately, causing the air temperatures to be higher, but the pavement itself to be cooler, the study found.
It’s important to note that the study was completed during hot, sunny days, which are extremely common in Los Angeles’ San Fernando Valley and that temperatures were not taken at night. That could mean that, in total, the cool pavement could reduce the surrounding temperatures, but still may not help those seeking relief in the middle of the day.
As we suspected previously, glare also increases with lighter roads that reflect sunlight. Ariane Middel, one of the researchers for the project, told CityLab that the coating adds up to 10% more sunlight to the affected areas and most of that is in the early evening during rush hour.
Light colored and reflective roofing materials and coatings are currently much more popular than pavement coatings, due to the benefits the interior of the building gains and the small amount of human activity that has to happen on the roof. It does make me wonder about contractors and mechanics that have to work on these lighter roofs, though: are they actually being exposed to higher temperatures in addition to the increased glare?
Full story: The Problem With ‘Cool Pavements’: They Make People Hot | CityLab
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