When a heatwave hits, temperatures in cities can become even more extreme as all that concrete and asphalt absorbs a ton of sunlight.
One Los Angeles neighbourhood is testing out a new strategy to keep itself cool from this phenomenon, called the “urban heat island” effect.
Pacoima, a community in the San Fernando Valley, is painting one million square feet of roads, playgrounds and basketball courts with a reflective paint. The paint doesn’t absorb as much heat as uncoated surfaces would, and project organizers hope that the effects can spread to cool down the whole neighbourhood.
On hot summer days, cities can get up to seven degrees Fahrenheit hotter than their surrounding areas, according to the US Environmental Protection Agency (EPA).
Even at night, long after the sun has set, cities can still be up to 5F hotter as absorbed heat radiates back out from roads, buildings and sidewalks, the agency adds.
The paint being used in Pacoima can reflect both visible light and infrared light - meaning heat, according to Fast Company.
Streets in the neighbourhood have been coated in a light-grey paint to bounce sunlight from the dark asphalt which can be a significant source of heat since darker colours absorb more heat than light ones.
The paint also comes in more colourful hues, and areas around a local park have been decked out in blue, white, yellow and brown. Different colours were used to delineate sections of basketball and tennis courts, as well as track and hopscotch courts.
...
Some initial measurements have shown promise. Bloomberg reports that an area of coated pavement was about 10F cooler than non-coated asphalt nearby, during one measurement in the neighbourhood.
That could make a significant difference. Standard pavement can reach up to 150F (67C) on a hot day, according to the EPA, meaning lots of extra heat seeping into the community.
and more:
https://www.independent.co.uk/climate-change/news/los-angeles-heat-pacoima-pavement-b2148821.html