The Oxygena line of floor tiles from Italian firm Gambarelli eliminates contaminating gases through its surface. The system is based in that the tiles contain titanium dioxide, an element which reacts to and eliminates polluting gases thus rendering them harmless. The company's website explains that when solar rays hit the surface of the tiles, titanium dioxide (thanks to its photo catalytic properties) produces active oxygen, which then oxidizes polluting gases. The gases are transformed into nitrate ions which, combined with water or other elements, become eco-efficient (scheme in the extended).
Oxygena is designed for outdoor applications (buildings, balconies, walkways, etc.), and it can help cleaning the air of nitric oxide and nitrogen dioxide produced by vehicles, central-heating systems and domestic cookers. It can also be laid indoors. ::Oxygena.