Human reactions to indoor air pollutants: N-decane

Abstract A dose-response study of human reactions to the indoor air pollutant n-decane was performed in a climate chamber. Sixty-three healthy subjects, randomly selected from the normal population, were exposed to n-decane concentrations of either 0, 10, 35, or 100 μL/L in a controlled, double blind study using a latin square exposure design. The most significant findings were dose-dependent changes in irritation of mucous membranes, increased sensation of odor intensity, and reduced air quality. Adaptation was seen at the highest exposure levels, but not at the levels relevant for a non-industrial environment. The physiological measurements showed decreased tear film stability at all exposure concentrations. The number of conjunctival polymorphonuclear leucocytes increased in a dose-related manner. Predictors of the sensitivity to explosure, i.e. mucous membrane irritation threshold and skin irritation (Stingers test), were correlated to subjective ratings of odor intensity and irritation of mucous membranes. In conclusion, even small concentrations of the relatively inert n-decane caused symptoms similar to those indicated in the World Health Organization definition of the sick building syndrome. Furthermore, physiological changes appear to be related to exposures to indoor air pollutants.