Paving Slabs that Clean the Air (IMAGE) Fraunhofer-Gesellschaft Caption Initial tests in the measuring chamber confirm that paving slabs coated with titanium dioxide can reduce ambient nitrogen oxide levels. Credit Fraunhofer IME Usage Restrictions The picture may be used for editorial purposes only. It is protected by copyright. The use is free of charge if the reference is mentioned. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.