Photocatalytic surfaces for the reduction of nitrogen oxide pollution on roads - TiO₂ pilot study noise barrier

To protect human health and vegetation, it is necessary to minimise air pollutants at highly polluted sites. This also includes improving air quality along transport routes. In the past, far-reaching measures have already enabled the limit values for fine dust particles to be largely complied with. At present, the focus is on reducing nitrogen oxide pollution in conurbations and on highly frequented traffic routes. BASt therefore initiated a pilot programme comprising several projects in which the nitrogen oxide reduction potential of titanium dioxide (TiO₂) was investigated under real conditions. The presented study describes the work carried out in connection with the application of a TiO₂ suspension on a noise barrier.
In summary, it was found that even in large-area applications of photocatalytic surfaces the very high reduction rates achieved in laboratory tests are not necessarily transferable into practice. Reliable reductions in pollutants are possible to a lesser extent if it is possible to avoid contamination by application at the right time of the year. To improve the effect, further investigations should be carried out under the most stable possible ambient conditions, e.g. in a tunnel.