Paving blocks with photocatalytic properties can make a measurable and lasting contribution to reducing urban air pollution and in particular 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 pollutants in situ are currently in the trial phase. Paving blocks with photocatalytic properties make an active contribution to protecting the environment and improving the quality of life in urban environments.