USA: Street grids may make cities hotter
By Linda Poon
By comparing buildings to water molecules, researchers found that the form of a city can intensify the urban heat island effect.
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By now, scientists know that the density of buildings, the absorption of light by those buildings, and the relative lack of vegetation in cities are major contributors to the urban heat island effect. It’s why cities like Chicago are hoping to find relief through green roofs and reflective construction materials, or through planting more trees and banning cars. In a more radical move, Los Angeles even began painting their roads white as part of Mayor Eric Garcetti’s effort to bring down the city’s temperature by just under 2 degrees over the next 20 years.
Yet Roland Pellenq, a senior research scientist at MIT’s Concrete Sustainability Hub, wondered how much the actual layout of a city area contributes to the intensity of the urban heat island effect. To find the answer, Pellenq and his team turned to physics.
In a paper published last month in the journal Physical Review Letters, he and his team concluded that the “texture” of a city makes a big difference. Grids may be making cities much warmer than nearby suburbs and countryside.
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