In Italy, a 1/4 mile stretch of concrete road, using, photocatalytic cement, (cement with titanium dioxide, a white pigment) was tested and not only did the road stay white, it purified the air above it! With traffic of over 18,000 cars a day, tests shows a reduction in nitrogen oxides of 60%.
In 2003, a church in Tor Tre Teste (Eastern Rome) was built of the same photocatalytic cement. Instead of being grey and covered with carbon pollutants, it is still a bright white. The concrete joints were not treated, and they are already grimy and dark.
Painters have long known that titanium dioxide, was a bright white pigment. But few people understood, or dreamed that this material actually absorbs and "eats" carbon based pollution.
Construction products containing titanium dioxide destroy coal and heating emmissions as well. These smog eating products can be used in paint, plaster, concrete, and almost any concrete surface, such as roads, drives or parking lots.
Melanie Sattler, professor of civil and environmental engineering at the University of Texas, in Arlington, Texas has wondered if use of these materials could reduce pollution in the atmosphere.
Sunlight starts a chemical reaction that accelerates natural oxidation, and breaks down nitrogen oxides emitted from fossil fuels. Italcementi, is the Italian company that has taken a lead in the research and use of this product. Pollutants are reduced within about eight feet of a surface that has been treated.
Enrico Borgarello, with Italcementi has worked to develop practical applications. Now a person driving a car or walking beside a building made with this product, would actually be breathing air 60% cleaner.