PhotoCatalyst TiO2 treated Brick Sidewalk that was installed to help reduce the level of pollutants (including NOx)
These are special Photo-Catalalyst TiO2 treated Bricks made to allow water to go through the bricks and are TiO2 treated on the top surface to reduce the level of airborne pollutants.
This Photo-catalyst TiO2 treated Sidewalk is slef-cleaning as the surface is cleaned when it rains .