Cities and other urban densities form so-called “heat islands”, areas where summer temperatures are higher than the surrounding land. rural type due to the accumulation of paved streets, concrete buildings and other surfaces that absorb a large amount of heat. Tackling this phenomenon is one of the challenges of the current climate emergency. Already in US and Qatari cities with asphalt a new cold pavement and with colors that absorb less heat.
A study published in the journal in 2020 Environmental Research Letters the use of certain coatings in two neighborhoods of Los Angeles. managed to lower the coating temperature by up to 10ºC.
At that time, a town in the Los Angeles area called Pacoima decided to coat the pavement of its streets and squares with an acrylic epoxy coating, which reflects heat from the sun, resulting in a light blue finish compared to the traditional black. Otherwise it will absorb the asphalt and make this neighborhood even hotter.
this pavement reflects the sun’s ultraviolet rays and absorbs solar radiation less, resulting in an overall drop in temperature.
“Pacoima is one of the warmest areas in Los Angeles County. One of the challenges of urban heating is that it doesn’t stop overnight. “We want to make this place a little more livable for its residents,” says Jeff Terry, president of the GAF company that led these studies.
The blue paved area is a ten-block neighborhood with parking lots, basketball courts, and a training center.
Similar systems have been tried in other neighborhoods, including the city of Los Angeles, even on white sidewalks, with encouraging results gathered by several scientific studies.
multiple advantages
Now, backers of the initiative at Pacoima have begun collecting data to confirm the effectiveness of this new coating at lowering temperatures. Haider Taha, president and scientist of Altostratus Inc, has been researching urban cooling for three decades, and the benefits of lowering the temperature in a city are not only related to the reduction of polluting emissions, but also to the reduction of pollutant emissions. less need for artificial cooling in homes and businesses.
Once the entire coating is complete, it is expected to take at least five years. “We want to learn here, and then we want to use these teachings to see if they can be applied both in the Los Angeles metropolitan area and in the San Fernando Valley, as well as in other cities and communities across the country,” San’a said. Diego newspaper Fernando Sun Jeff Terry, director of the GAF company, which donated material for the new pavement.
Research papers also indicate that the cold coating material reduces heat-related diseases, slows down the formation of fog, improves pedestrians’ ability to use the road and improves traffic safetylight-colored sidewalks better reflect streetlights and headlights, making vehicles more visible to drivers.
Additionally, by lowering the air temperature in residential areas, cool cladding can slow chemical reactions in the atmosphere. smoke.
The cooled cladding material can be made from conventional cladding materials such as concrete. Reflecting around 50 percent of sunlight, the new concrete asphalt layer coating consists of four layers of primary layers, followed by three consecutive layers that reduce heat absorbed by solar radiation.
Actually, the simple use of light-coloured pavements already serves to soften the effect of ‘heat islands’. Researchers at the MIT Institute of Technology have shown that building lighter colored and more reflective roads has the potential to lower air temperatures by more than 1.4°C, resulting in a 41% reduction in the frequency of heatwaves in US cities. But reflective surfaces need to be used strategically – the wrong location can heat nearby buildings rather than cool them.
Also on the streets of Qatar
But this town in Los Angeles’ San Fernando Valley isn’t the only place where this venture has been launched. In extremely hot Qatar, authorities also launched an operation. pilot project to paint two of the capital’s main urban arteries blue. There the scope of the test is more modest because it is limited to two sections of 200 meters each on city streets.
Special devices and sensors were installed to measure the effectiveness of the material in reducing the ambient temperature in the asphalt. In this case, the project is carried out in cooperation with the Japanese Oriental Company.
Reference Work: https://cshub.mit.edu/sites/default/files/images/Albedo%201113_0.pdf
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Source: Informacion
