Countering Climate Change With Cool Pavements
upstart writes:
Countering climate change with cool pavements:
Pavements are an abundant urban surface, covering around 40 percent of American cities. But in addition to carrying traffic, they can also emit heat.
Due to what's called the urban heat island effect, densely built, impermeable surfaces like pavements can absorb solar radiation and warm up their surroundings by re-emitting that radiation as heat. This phenomenon poses a serious threat to cities. It increases air temperatures by up as much as 7 degrees Fahrenheit and contributes to health and environmental risks - risks that climate change will magnify.
In response, researchers at the MIT Concrete Sustainability Hub (MIT CSHub) are studying how a surface that ordinarily heightens urban heat islands can instead lessen their intensity. Their research focuses on cool pavements," which reflect more solar radiation and emit less heat than conventional paving surfaces.
[...] Cities like Los Angeles and Phoenix have already conducted sizeable experiments with cool pavements, but the technology is still not widely implemented. The CSHub team hopes their research can guide future cool paving projects to help cities cope with a changing climate.
[...] We can build cool pavements in many different ways," says Randolph Kirchain, a researcher in the Materials Science Laboratory and co-director of the Concrete Sustainability Hub. Brighter materials like concrete and lighter-colored aggregates offer higher albedo, while existing asphalt pavements can be made cool' through reflective coatings."
CSHub researchers considered these several options in a study of Boston and Phoenix. Their analysis considered different outcomes when concrete, reflective asphalt, and reflective concrete replaced conventional asphalt pavements - which make up more than 95 percent of pavements worldwide.
Journal Reference:
Hessam AzariJafari, Xin Xu, Jeremy Gregory, et al. Urban-Scale Evaluation of Cool Pavement Impacts on the Urban Heat Island Effect and Climate Change [open], Environmental Science & Technology (DOI: 10.1021/acs.est.1c00664)
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