Researchers Say Pavement Laced With Titanium Dioxide Removes Nitrogen Oxides

Researchers Say Pavement Laced With Titanium Dioxide Removes Nitrogen Oxides

Dutch researchers say a stretch of road paved with concrete containing titanium dioxide has been shown to remove up to 45 percent more nitrogen oxides than a comparable stretch of road not containing the photocatalytic material.

The tests conducted by researchers at the Eindhoven University of Technology in Eindhoven, Netherlands, were carried out in the municipality of Hengelo, where a busy road was resurfaced last fall.

As part of the project, 1,000 square meters of the road's surface were covered with the air-purifying concrete paving stones, the university reported. For comparison purposes, another area of 1,000 square meters was surfaced with normal paving stones.

Tests showed the material reduces the concentration of nitrogen oxides by 25 to 45 percent, according to Jos Brouwers, professor of building materials at the university.

"The air-purifying properties of the new paving stones had already been shown in the laboratory, but these results now show that they also work outdoors," Brouwers said. Further measurements are planned later this year.

Vehicle exhaust gases contain nitrogen oxides, which contribute to acid rain and smog. Titanium dioxide removes nitrogen oxides from the air and converts them, with the aid of sunlight, into harmless nitrate. The nitrate can then be rinsed away by rain.

The stones are said to be 50 percent more expensive than normal concrete stones, but  the total road-building costs are said to be only 10 percent higher.

Scott Doggett:  is an AutoObserver.com Associate Editor.