Human reactions to a mixture of indoor air volatile organic compounds

A controlled experimental study of human reactions to a mixture of 22 volatile organic compounds often found in indoor air was performed in a climate chamber. Twenty-one healthy subjects were compared with a group of 14 subjects suffering from the ‘sick building syndrome’ (SBS subjects), i.e. having symptoms related to the indoor environment (irritated mucous membranes, headache, etc.) as defined by WHO in 1982. In groups of 4 these subjects were exposed during two successive periods to either 0 and 0 mg m⁻³, 25 and 0 mg m⁻³, or 0 and 25 mg m⁻³; 25 mg m⁻³ is equivalent to the highest concentrations expected in a new building. The study was double blinded, and a latin square design was used to balance out effects of day in the week and season. Both groups reacted subjectively to the air reporting worse odor, worse indoor air quality as defined by the subject, and more irritated mucous membranes in eye, throat and nose than in the clean environment. A tendency to a stronger response was seen among the SBS subjects. Objective measures indicated among others an exposure related reduction in lung function among SBS subjects. Both groups had an increased number of polymorphonuclear leucocytes in tear fluid as a result of exposure. This was not seen for nasal secretions. Psychological performance tests indicated an exposure related diminished ability to learn. In conclusion, the experiment indicates that exposure to volatile organic compounds in low concentrations as seen in new houses causes both subjective complaints and objective signs in normal healty subjects; but more so in subjects from the sick building syndrome.