French company Eurovia will be installing paving slabs that absorb air pollution in Kendal, Cumbria, next month. The name for the product is NOxer®.
The technology seems to be covered by their granted European patent Coating composition for sound-absorbing and pollution-abating facings, which is in French (but the claims are in English and German as well as French, see pages 5-6).
In addition, the text of the description can be translated by asking for it (in the left hand column) and then clicking on the Patenttranslate button. The results are really rather good -- you can understand what the invention is about. This function is "powered by EPO and Google" and is free. This is a recent revision of the earlier machine translations and helps when, as in this case, there is not an English language equivalent document.
So how does it work ? The coating is a mixture of spruce wood, cement, water and titanium dioxide. When it receives ultraviolet sunlight, it is able to absorb nitrogen oxide, which is emitted by car exhausts. The pollutants become nitrate ions, which are either washed away by rain or absorbed harmlessly into the paving.
The new paving has already been used in many towns in Japan. Eurovia has a page about the product. It sounds like a very interesting development, though I'm not clear how much more expensive it is than normal paving, and how effective it is in reducing air pollution for the pedestrians.