Self-help for city hygiene

A new type of cement based on the increasingly useful titanium dioxide could be used to coat sidewalks and destroy pollutants when the sun shines, according to Karin Pettersson of Swedish construction giant Skanska. Skanska, Cementa, and several other companies are participating in a US$1.7 million (€1.4m) Swedish-Finnish project to develop catalytic cement and concrete products coated with titanium dioxide. Photocatalytic cement has already shown its prowess in city testing where nitrogen oxide levels were reduced by up to 60% depending on the weather conditions as the titania photocatalyzes their degradation to nitrates. Other experiments have produced results between 20 and 80%. Optimizing the formulation for particular applications could make the materials viable for use in the construction industry and bring about a titanium dioxide-fueled war on pollution.