The effect of ventilation on volatile organic compounds produced by new furnishings in residential buildings

It can be difficult to tease apart the sources of the many chemical substances that can adversely affect indoor air quality (IAQ). These can be generated from primary sources, e.g. cleaning products, fragrances and wall decorations, and created in-situ (secondary emissions). Inputs due to human activities (heating, smoking, etc.) add to the catalogue of chemical possibilities. This study examines the effect of airtightness and ventilation on volatile organic compounds (VOC) concentration in newly-furnished unoccupied residential houses. Further objectives included investigating the effects of airtightness and mechanical ventilation on internal VOC concentrations in two rooms with controlled simulated occupancy. Chemicals that appear to have been generated directly from or supplemented by furnishings were acetone, 2-butanone, ethyl acetate and tert-butyl alcohol. In the absence of mechanical ventilation, total VOC (TVOC) concentrations were over three times greater in the more airtight room. The appearance of concentration maxima after furnishing and/or decoration was delayed in the airtight room and the subsequent decay rate was slower. With the exception of benzene, none of the individual compounds exceeded national guidelines for outdoor air (in the absence of IAQ guidelines). Mechanical ventilation reduced TVOC concentrations by 300 mu g m(-3) (more airtight room) and > 340 mu g m(-3) (less airtight room) to below European threshold recommendations; although the reduction took approximately five days. The time lag indicates that simply providing adequate ventilation during chemical use indoors may not be sufficient to protect inhabitants from prolonged exposure following use.