Reactions among pollutants in the intake air can increase the concentrations of irritating and hazardous products in the indoor air and may lead to an increase of the sick building syn-drome (SBS). A short description of an experimental set-up that enables the studies of the impact of different settings of a full scale ventilation system on air with different ambient compositions is presented. Preliminary sampling using Tenax TA show that some reaction rates are increased in the experimental set-up, which could indicate that heterogenous reactions occur.
Thirty female subjects were exposed for 280 minutes to four conditions in balanced order of presentation: to 20 C/40%, 23 C/50%, 26 C/60% RH at10 L/s/p outside air, and to 20 C/40% RH at 3.5 L/s/p. They performed simulated office work throughout each exposure and repeatedly marked a set of visual-analogue scales to indicate their perception of environmental conditions and of the intensity of SBS symptoms at the time. They were repeatedly reminded to adjust their clothing so as to remain in thermal comfort, and succeeded in doing so.
Relationship between sick building symptoms and type of heating system were investigated through a questionnaire in 4815 dwellings from 231 multi-family buildings built before 1961. Results do not demonstrate that energy savings measures in general increase the risk of sick building syndrome, but major reconstruction of old dwellings may increase this risk.
A 2x2 replicated field intervention experiment was conducted in a call-centre providing a public telephone directory service: Outdoor air supply rate was 8% or 80% of the total airflow of 430 L/s providing 3.5 h-1; and the supply air filters were either new or used (i.e., used in place for 6 months). Each of these 4 conditions was maintained for a full working week at a time. Room temperature and humidity averaged 24 C and 27% RH.
This paper provides a summary of current knowledge about the associations of ventilation types in office buildings with sick building syndrome symptoms. Most studies completed to date indicate that relative to natural ventilation, air conditioning, with or without humidification, was consistently associated with a statistically significant increase in the prevalence of one or more SBS symptoms, by approximately 30% to 200%.
This study investigated if low air temperature, which is known to improve the perception of air quality, also can reduce the intensity of some SBS symptoms. In a low-polluting office, human subjects were exposed to air at two temperatures 23 C and 18 C both with and without a pollution source present at the low temperature. To maintain overall thermal neutrality, the low air temperature was partly compensated for by individually controlled radiant heating, and partly by allowing subjects to modify clothing insulation.
A survey was conducted in a new office building in Beijing (China) with mechanical air supply and natural exhaust, in which sick building symptoms were reported. Measurements and data from a questionnaire suggested that ventilation was insufficient.
30 human subjects were exposed to simulated office conditions to study perceived air quality and sick building symptoms. The sensory pollution load of personal computers was found to be 3 olf each.
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