Impact of a photocatalytic oxidation layer covering the interior surfaces of a real test room: volatile organic compound mineralisation, risk assessment of by-product and nanoparticle emissions.

Many studies about photocatalytic oxidation (PCO) have been carried out in laboratories. They use an inert test chamber with ideal indoor conditions: a low volume, a controlled temperature and humidity, and a constant injection of one to five specific gases. The principal aim of this study was to implement, in a real test room (TR) of an experimental house, a titanium dioxide (TiO2) layer to quantify its efficiency. This layer, directly in contact with the indoor air (IA), was one of the four layers embedded in a passive system (PS) specifically designed to improve the indoor air quality (IAQ) and the thermal comfort. A specific monitoring in the TR assessed the removal rate of the volatile organic compounds (VOCs), as well as formaldehyde (HCHO) as a possible intermediate, and the nanoparticle (NP) emissions. In addition, a comparison was made with a reference room (RR) which was not equipped with the PS.