Abstract

Threshold responses of odor, nasal pungency, and eye irritation were measured for single chemicals and mixtures of them. Nasal pungency was measured in subjects lacking a functional sense of smell to avoid interference from olfaction. Various degrees of stimulus agonism were observed for each of the three sensory channels when testing mixtures. As the number of components and the lipophilicity of such components in the mixtures increased, so did the degree of agonism. Synergistic stimulus agonism characterized the eye irritation response for the most complex and the most lipophilic mixtures. Physicochemical properties play a large role in the determination of sensitivity to airborne chemicals, particularly to their ability to evoke irritation. Whereas this has revealed itself previously with respect to single chemicals, it seems to have relevance to mixtures as well.