Bio-based plaster for improved indoor air quality

Abstract

People in industrialised countries spend approximately 80% of their time indoors. As such, the internal environment quality can have a significant impact on occupant health and wellbeing. Additionally, the demand for increased building energy efficiency has the potential to degrade Indoor Air Quality (IAQ) through a reduction of air exchange rates. In many forms of construction, the walls and ceilings are plastered, providing a large surface area exposed to the indoor environment. There is a growing recognition of the important role this surface may have on IAQ through regulation of relative humidity. Another, less well known, impact is that porous coatings have the potential to adsorb Volatile Organic Compounds (VOCs) from the air, which offers further potential to improve IAQ. This paper presents work from the development of a novel bio-based plaster with improved hygrothermal performance and VOC sorption characteristics. Cellulose flakes, used for blown insulation, were added into a cement-lime substrate in three different proportions. A range of mechanical, hygrothermal, VOC emission and VOC adsorption properties were investigated to evaluate the potential of the bio-based cementlime plaster to improve IAQ. The bio-based cement-lime plaster resulted in an improved thermal conductivity and an improvement in the material’s moisture buffering capacity and VOC adsorption capacity. With 5% addition of cellulose flakes, the hygrothermal performance increased by over 25%. This material also showed the ability to capture VOCs and formaldehyde from the air, reducing the concentrations of these compounds by up to 22% and 70 % respectively. Therefore, the impact of the implementation of this plaster includes potential benefits regarding better operational performance of the building and improved occupant health and wellbeing.