Humidification and perceived indoor air quality in the office environment.

The aim of the study was to evaluate the effect of humidification on the odour, acceptability and stuffiness of indoor air. The air of two wings of an office building in turn were ventilated with air of 30%-40% humidity in a six period cross over trial. The third wing was used as a non-humidified control. A panel assessed the quality of indoor air weekly. Mean intraindividual differences were used to assess the roles of sex, current smoking and age. The study found that humidified air was regarded as more odorous and stuffy than non-humidified air. Women and non-smokers found the differences greater. The oldest age group found the least differences while the youngest age group found the greatest differences. The differences were not found to be statistically significant. Concludes that an untrained panel of twenty people is able to differentiate a slight bad odour and stuffiness in indoor air and that steam air humidification decreases the perceived air quality.