The Latest Smog-Eating Weapon Might Just Be Your Roof

We all know that getting more pollution-spewing cars off the road is the solution to curbing the globe’s dismal air-quality situation. In the meantime, crews of scientists across the world have been busy developing technology that destroys the toxic fumes coming out of automobile tailpipes. The latest effort comes from a team of clever chemical and environmental engineers at the University of California, Riverside. They’ve come up with a coating for roofs that eats the smog emissions equivalent of a car driven 11,000 miles per year.

The roof coating, which is simply a paint made from titanium dioxide, the same chemical in plenty of commercial sunscreens, is photocatalytic. Once it’s painted on a surface and particulate matter in air pollution comes in contact with it, the smog turns into harmless inert salts. Architects from Italy to China are constructing buildings made out of these kinds of materials, and even the U.K. has a smog-killing poem. But the UC Riverside solution is perhaps the most practical and cost-efficient of all. Paint can be placed anywhere, and the team estimates that it would cost $5 to produce enough coating to cover the roof of a 2,400-square-foot house.

The students hope to expand beyond covering roofs. “Our goal is to apply this coating on any surface that hits direct sunlight,” says Jessica Moncayo, one of the students who worked on the project. To that end, the team has big ideas, such as painting freeways with the coating. “Having the coating on freeway dividers allows the coating exposed closer to one [nitrous oxide] emission source—vehicles.

So will this pollution-killing technology become available for you to paint on a roof anytime soon? Many students from the UC Riverside team graduated last June. Moncayo says she’s not sure how many new students have stepped up to continue the research, and additional funding is needed. It seems like the kind of idea that a paint company would be keen to help out with. However, if a new research crew at UC Riverside is assembled, it’ll need to conduct more effectiveness trials and figure out what works best. “Testing additional parameters will allow us to optimize and prove the sustainability of the coating,” says Moncayo.

Right now, one challenge in bringing the coating to market is that it’s only available in white, and not everyone wants a roof painted that color. However, that’s not a bad problem to have; it’s been proven that a white roof reflects 90 percent of sunlight whereas a black roof reflects just 20 percent. That means our cities could be less smoggy and cooler.

Moncayo says that the team’s professors have been contacted by government agencies in the U.S. and abroad.

“This is good news since our coating was to be cost-effective enough to spread to other countries experiencing poor air quality as well,” she says. Getting the public informed of such efforts to improve air quality is crucial, she adds. If the public demands simple solutions, like a coating that can eat smog, politicians and policy makers are more likely to get the ball rolling and make that happen.