In good news for urban health, a U.S. company has invented a spray-on material that cools the city and improves air quality.
The spray-on treatment, called A.R.A.-1 Ti, has been developed by Pavement Technology Inc and Louisiana State University. Its base is titanium oxide, a common ingredient in sunscreen, and works as a photocatalyst, absorbing and dispersing heat and light from roads. So, rather than simply radiating heat, roads now generate cooler temperatures.
In addition to lowering the temperature, the spray has two further tricks up its sleeve: it absorbs car exhaust fumes, thereby improving air quality. The company claims that spraying one mile of road with the product offers the same air quality benefits as planting 20 acres of trees. Furthermore, the snappily named A.R.A.-1 Ti can also rejuvenate aging roads, reducing the frequency of repaving.
This isn't just an interesting concept. Last year, Orlando International Airport in Florida used the treatment, and researchers found it cut nitrogen oxide pollution essentially in half. On the strength of those results, the cities of Orlando, Charlotte, Raleigh, Greenville, and Charleston are now all currently testing out the product.
Of course, the spray isn't a solution within itself. Cities will still have to focus on greening up their environment through emission reductions and tree planting, but the spray looks set to be a useful addition to the armoury.