EU project developing construction materials to absorb pollution

Brussels, 05 Mar 2004

Researchers from private enterprises, research institutions and the European Commission's Joint Research Centre (JRC) are currently working together on the development of smart construction materials capable of absorbing and washing away pollution.

The PICADA (photocatalytic innovative coverings applications for de-pollution assessment) project is working with materials such as plaster, mortar and architectural concrete containing titanium dioxide (TiO2), which is able to capture organic and inorganic air pollutants after they have been exposed to ultra violet or the Sun's rays.

'Smart coatings can cause a revolution, not only in the management of air pollution, but also in how architects and town planners tackle the persistent problem of urban smog,' said EU Research Commissioner Philippe Busquin.

The chemical reactions that enable the absorption of pollutants are the following: The pollutant substance is adsorbed onto the covering surface and comes into contact with TiO2. TiO2 then absorbs the energy of the photons coming from UV radiance and releases it as water molecules into the atmosphere to create free radicals. These radicals are extremely reactive oxidisers that act on absorbed pollutant particles. The acidic products created by this process are washed away by rain or neutralised by alkaline calcium carbonate contained in the materials.

The materials have yet to be used outside of laboratory testing conditions, but preliminary tests with similar photocatalytic materials under field conditions indicate that air quality can be significantly improved.

In 2002, 7,000 square metres of road in Milan, Italy, were covered with a photocatalytic cement-like material. The result was a reduction in the concentration of nitrogen oxides at street level by up to 60 per cent. Similar results have also been obtained in Japan.

The project is expected to be instrumental in helping to meet the EU target of reducing nitrogen oxide levels to under 21 parts per billion by 2010. While attention is currently focusing on the development of innovative materials for outdoor use, future research is expected to assess the feasibility of using de-polluting materials and coatings in indoor environments.
For further information on the project, please visit:
http://www.picada-project.com/domino/Sit ePicada/Picada.nsf?OpenDataBase

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