The United States has long employed a technique used by our grandparents' grandparents to deal with high summer temperatures: painting white surfaces. But in this case it is not a normal paint, there they use a titanium dioxide-based coating which, apart from repelling heat, captures and decomposes toxic exhaust emissions.
Anyone who lives in a city knows what it means to go outside in the middle of July, when the sun is at its highest. It's easy to get lipotimia just thinking about it. In the 19th century, the Anglo-Saxons gave a name to this extreme heat that occurs much more intensely in cities than in the countryside: the 'urban heat island'.
The urban heat islandrefers to the increase in temperature caused by human activity. Tall buildings blocking the air flow, asphalted streets, metal roofs or concrete pavements make temperatures much higher than in places where nature is more present.
To combat this problem, many American cities have long opted for a remedy that has been used for generations in hot countries like ours, painting surfaces as floors, walls and ceilings in white. But the paint being tested in some of the hottest states such as North Carolina, Orlando or Florida does more than just dissipate the heat, it also, according to comment its creators to the British media The Independent, can reduce tailpipe emissions by 30%.
Asphalt is made from tar, crushed rock, sand or gravel. All asphalts have two molecular structures in common: maltenes, which are responsible for holding the elements together, and asphaltenes, which give the road its black colour and firmness. Over time, maltenes eventually break down and roads crack.
This material, created by the US company Pavement Technology, is called Plus Ti and promises to be a rejuvenating treatment for roads. It is made from titanium dioxide, a compound that is capable of repairing maltene and restoring its original characteristics. Moreover, it is not white, but yellowish and is applied to the road by spray trucks like a sunscreen that disperses the sun's radiation, cooling the roads and reducing the 'urban heat island' effect.
Ken Holton, a technical consultant at Pavement Technology, says the product is capable of extending the life of roads if applied just after the asphalt is laid. "It's very exciting," says Holton. "We thought that reducing tailpipe emissions and cleaning the air for people to breathe was important. And suddenly heat island [reduction] seems to be an important thing as well."
The company also calls this compound "smog eater". When titanium dioxide is exposed to sunlight, it is capable, according to the company, of capture and decompose toxic emissions emissions from exhaust pipes, as well as the nitrogen oxides and volatile organic compounds that make up 'smog' - that mixture of smoke and haze produced by car emissions.
Pavement Technology is collaborating with Texas A&M University to see what role titanium dioxide plays in the breakdown of microplastics. It has uncovered that tyre wear is a major producer of tiny plastic pieces that end up in our oceans and that end up in our fried fish, our marinated dogfish or our cod.
