Smog Eating Concrete
An Italian firm has patented a concrete mix that photocatalyzes nitric oxide pollutants in the air, breaking these smog creating compounds into less harmful carbon dioxide, nitrates and water.
Best performance is achieved in architecture with large surface areas and direct sunlight in locations with high traffic flows--urban. An additional benefit is the long term preservation of bright, clean concrete surfaces. The cement is white and the installation can be precast, plastered, or cast in place.
Results show a 45 to 60% reduction in nitric oxides via photocatalysis. Cost of the concrete is 30 to 40% greater, but I would look at a plastered surface with this admix. Test results in Milan showed covering 15% of visible urban surfaces with this material enables a reduction in pollution of approximately 50%.
Projects using photocatalytic cements [.pdf].
