In the current context of climate change, and as a highly emissive sector, the construction sector has set in profound changes. One of these changes implies the development and use of bio-based materials, and particularly for insulation materials, bio-based products already represent a large part of the market. Bio-based insulation materials reduce their carbon footprint by incorporating biological fibres, such a hemp, wool or wood, hence reducing the use of high energy demanding mineral counterparts. Due to their high organic content, bio-based materials can form a considerable source of Volatile Organic Compounds (VOCs) and may offer a favourable environment for the development of micro-organisms. The project Emibio was undertaken to evaluate the contribution of these new insulation materials to IAQ, and more specifically, which and how much VOCs they emit and if they offer a favourable environment for microbial development. Here we focus only on VOC emission. To verify the influence of these materials on the IAQ, a recent public building was selected, constructed using bio-based materials. The experimental room in the school, located in the North of France, had 3 exterior walls made of wooden modules, containing 36 cm blown-in cellulose insulation and covered with plasterboard. The emissions of these materials were monitored in-situ but also measured from each of the materials individually in a test chamber. In-situ sampling was done on adsorbent tubes and cartridges using a Field and Laboratory Emission Cell. VOC emissions from new materials were monitored in a Climpaq test chamber under controlled conditions of temperature, humidity and air exchange rate, following the ISO 16000 standards. The analyses for both sample types was done by GC-MS/FID and HPLC-UV. The measurements in the test chamber showed that the most emissive element in the wall was the OSB wood panel, followed by the wood used for the frame ([TVOC] = 239 and 184 µg m-2 h-1 eq. toluene resp.). Slightly lower TVOC concentrations were obtained for the cellulose insulation (109 µg m-2 h-1 eq. toluene). The emissions from glass wool, a conventional insulation material, were also measured as a reference ([TVOC] = 3.5 µg m-2 h-1 eq. toluene). VOCs measured in the test chamber were however not necessarily found in the samples taken in-situ nor were they major contributors to the VOCs measured in the ambient air of the room. This study puts the contribution of individual material emissions in perspective and underlines the importance of the history of use of the materials.