Pollution through nitrogen oxide (NO) and nitrogen dioxide (NO2) has become one of the largest air quality problems in urban areas, with many cities worldwide overshooting national and international concentration threshold values. There are very few options to reduce NO and NO2 pollutants, excluding the removal of combustion engines out of urban areas.
One of the passive strategies to lower NO, NO2 and subsequent Ozone in urban areas is the use of photocatalytic active surfaces. These surfaces, including titandioxid present in materials and paint, are able to absorb NO and NO2 out of the air and transform it into solid nitrate which can be washed away with the rain.
The Innovation City Bottrop Project is a large think tank and demonstration project in the Ruhr area (http://www.icruhr.de). Together with STEAG Powerminerals and the TU Berlin, ENVI_MET investigated the potential of using photocatalytic surfaces (ground surface and facades) to reduce the NO and NO2 level. Several simulations have been performed for the inner city district of Bottrop using different meteorological situations and varying levels of active surfaces using the PHOTOMET material from STEAG Powerminerals.
Depending on the level of active surfaces and of the traffic NOx load, a local reduction of 5% to 14% NO and 4% to 6% NO2 could be achieved using this passive technology.