To help reduce the accumulating levels of dangerous nitrogen oxide released by most vehicles into the environment, scientists have developed an anti-pollution tile that can be applied to the roofs of normal buildings. At its base, this product is made of concrete like most protective roof tiles, but it contains an important chemical instigator that activates with the ultraviolet content of sunshine. The Smog Eating Tile works with a sustainable photocatalyst built into its makeup. In the light of day, each tile starts to break the pollutant compounds of smog down into harmless calcium nitrate (which washes away with rain and actually nourishes plant growth in soil). It is estimated that 2 000 square feet of the Smog Eating Tile gobbles up the same amount of pollutants produced by a regular car that has been driven 17 500 kilometers during a single year.