Sunlight in combination with photocatalytic materials can clean facades, decompose airborne or water-borne pollutants, and kill bacteria, algae and fungi. The light rays (usually UV light) break down organic contaminants into H2O and CO2. As one of eleven partners in the PureBau joint project, the Fraunhofer IST is conducting research on the photocatalytic effectiveness of titanium dioxide, which is added to building materials such as concrete, facade paints, roof tiles and glass. The goal is buildings that clean themselves while cleaning the air at the same time.
Photocatalytic efficiency nevertheless varies depending on the pollutant, product and respective mixture. It is also hard to predict the long-term behavior and stability of such building materials outside the lab. This is where the mobile measuring gun, which was developed together with the company Omicron Laserage Laserprodukte from Rodgau near Frankfurt, comes in: it can determine the decay of luminescence due to UV radiation and the photocatalytic activity of surfaces even outside of the laboratory. It should be ready for the market in one to two years.