Paving blocks with photocatalytic properties can make a measurable and lasting contribution to reducing urban air pollution and in particu- lar NO2. Their effect has been proven scientifically by many research projects. Equally, their suitability for use in practice has been proven over a period of nearly 10 years. Simple methods for testing the efficacy and for quality assurance with regard to the degradation of pollu- tants in situ are currently in the trial phase. Paving blocks with photocatalytic properties make an active contribution to protecting the envi- ronment and improving the quality of life in urban environments.