Air-purifying paving

Researchers at the University of Twente have developed air-purifying stones that will pave a section of road in the municipality of Hengelo in the eastern Netherlands.

Car exhaust fumes contain nitrogen oxides that can cause acid rain and smog. The researchers believe that the problem can be partly solved by using the air-purifying paving stones.

The top layer of the paving stones is made of air-purifying concrete that contains titanium dioxide, a photocatalytic material that uses sunlight to convert the nitrogen oxides in the air into harmless nitrates.

Although the idea was originally conceived in Japan, it was developed further by Dutch researchers at the university's concrete research laboratory.

In the trial to assess the effectiveness of the stones, which is being carried out in conjunction with stone producer Struyk Verwo Infra, a street in Castorweg will be divided into two sections: one half will be paved with conventional stones and the other half with air-purifying ones.