Scientists take smog fighting to the streets

Wed, 2014-07-23 06:00 -- Kevin Ebi

While air pollution has been a concern for centuries, there’s no question that cars have made the problem much worse. But now the very thing that allows so many people to drive may also play a big part in cleaning up.

Dutch scientists have invented an air purifying pavement that is showing promise.

Long-term tests on one street in the Netherlands show the pavement can cut the amount of nitrogen oxides in the air by nearly half under ideal weather conditions. Nitrogen oxides are a group of poisonous gases that react with other compounds in the air to form smog.

How it works

The technology itself is relatively simple. The cleansing pavement is made by simply coating paving blocks with titanium oxide. Titanium oxide reacts with nitrogen oxide, turning the poisonous gas into less harmful nitrates.

The reaction works best on days when there is intense sunlight and low humidity. On those ideal afternoons, the pavement cut pollution by 45%.

But it seems to help even when the weather isn’t perfect. Over the course of an entire year, it cut pollution by 19%. That includes mornings and dreary days when direct sunlight was in short supply.

Benefits for cities

Despite the dramatic cleaning properties, the pavement itself isn’t especially expensive. It costs about 10% more than conventional pavement, although the coating does lose its effectiveness over time.

And just as air pollution is caused by more than cars, applications for the cleansing technology also extend beyond roads. The company that invented the process used the purifying concrete on its own research lab in Bergamo, Italy.

Read more about more pollution solutions…

Improved sensor technology shares real-time air pollution data

Air-purifying billboards? Engineers in Peru say they've created one

Big plan, big money will tackle Beijing's big air quality problem