Influence of eco-materials on Indoor Air Quality

A growing strategy to reduce the energy consumption of buildings involves a combination of increased air tightness and high levels of insulation. However, an undesirable consequence of this approach is a deterioration of the Indoor Air Quality and accumulation of airborne pollutants, resulting from the reduction in ventilation. The chemical nature and concentration of indoor air pollutants is dependent on the building materials and activities of the occupiers. Recent studies have raised awareness of the effect of Indoor Air Quality on the perceived comfort levels, health and well-being of humans. This paper investigates the role of commercially available natural building materials including lime mortars, natural fibres and wood panels on the Indoor Air Quality. Initially the emissions of Volatile Organic Compounds (VOCs) from building materials were identified and measured. Subsequent tests then considered the adsorption and re-emission behaviour of four VOCs; toluene, limonene, dodecane and formaldehyde. The significance of this paper lies in its demonstration that emissions are dependent on the chemical composition of building materials and the production process, whereas the adsorption/desorption characteristics are related to material microstructure and polarity of the VOCs. The results allow the performance of a construction material, in terms of its influence on indoor air quality, to be deduced from a knowledge of chemical composition and microstructure. This paper provides a new approach for assessing the influence of different building materials on indoor air quality when exposed to gaseous pollutants.