Pollutant absorbing buildings

The International Herald Tribune posted an article online last Wednesday that sounds too futuristic to be true, but it apparently is.
Architects in Italy are using a new type of concrete which is not only able to clean itself, it also can reduce pollutants in the air by a considerable amount in close range around the material.



image is property of International Herald Tribune

Extensive testing, sponsored in part by a European Union research project into "smart" antipollution materials, has since determined that construction products containing titanium dioxide help to destroy air pollutants found in car exhaust and heating emissions, scientists say.
Several companies are now developing "smog-eating" products that can be used not just for the facades of buildings, but also in paint, plaster, and paving materials for roads. The new environment- friendly substances are quietly being tried out in buildings, squares and highways in Europe as well as Japan.
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Titanium dioxide had been used in self-cleaning coatings before because of its photocatalytic properties: sunlight touching the compound triggers a chemical reaction that accelerates natural oxidation.

Upon testing its new cement, however, Italcementi realized that the material also had the ability to break down nitrogen oxides emitted in the burning of fossil fuels.
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The reduction of pollutants is greatest within 2.5 meters, or 8.2 feet, of a surface that has been treated, the company said. This means that a pedestrian walking down a street with traffic would inhale fewer pollutants while walking past buildings treated with the substance.

In one test, paving material using photocatalytic cement was used to cover the asphalt surface of a 230-meter- long stretch of road outside Milan with an average traffic flow of 1,000 vehicles per hour. Tests showed a reduction in nitrogen oxides at street level of about 60 percent, according to Italcementi.