Researchers from Nanyang Technological University (NTU) coated roofs, walls and pavement in Singapore's industrial areas with paint containing additives that reflect solar heat, according to research published in the journal Sustainable Cities and Society in March. Such studies suggest that paint could be a key tool in making cities more comfortable for working and playing in a warming world.
How can cool paint help reduce heat in cities?
After painting an area of the city with cool paint, they compared temperature and comfort levels with a neighboring, unpainted area.
The researchers measured air movement, surface and air temperature, humidity, and radiation over a two-month period and found that the coated areas reduced heat release from the building surface by 30%. This resulted in temperatures dropping by up to 2 degrees Celsius on the hottest part of the day.
The paint contains additives that reflect solar heat, successfully reducing surface heat absorption and emission. Compared to traditional roofs, roofs with cool paint coatings reflected 50% more sunlight and absorbed 40% less heat during the hottest part of a sunny day, reducing the temperature in the area by approximately 1.5 degrees and making it more comfortable for pedestrians.
The least intrusive solution for cooling cities
The findings could be invaluable to cities seeking quick, cheap ways to combat the damaging and debilitating effects of heat waves.
“This is the lowest-impact solution for cooling cities, and it’s immediate compared to other solutions that typically require large-scale urban reconstruction to deploy,” said Kiran Kumar Donthu.
By reducing the amount of heat absorbed by urban structures, it would also keep buildings cooler and reduce the need for indoor air conditioning, he added.
This is useful not only in cities like Singapore, which are hot year-round, but also in other urban areas affected by global warming.
"As the world warms, people will increasingly look for ways to stay cool," said lead researcher Associate Professor Wan Man Pun. "Our research validates how cool paint coatings could be a strategy for reducing the urban heat island effect in the future."
The NTU team will conduct further research, focusing on how the cold paint coating remains constant over time at the same experimental location.
Sources:
euronews.green (2024.04.01) ‘A minimally intrusive solution for urban cooling’: This paint could make cities feel 1.5C cooler
