An integrative approach considering acute symptoms and intensity ratings of chemosensory sensations during experimental exposures.

Even at low concentrations airborne chemicals can excite olfactory and trigeminal receptors and inform the organism about the presence of airborne chemicals. Acutely, malodors or sensory irritations might trigger symptoms (e.g., bad air quality, eye irritations) and in the long-run functional impairment of chemoreception might occur. In humans, knowledge about short-term adaptational processes and effects of exposure peaks on these systems is limited. Therefore, two different experiments with human volunteers were conducted. In experiment A exposures (4h) with fluctuating concentrations of 2-ethylhexanol (1.5, 10, 20ppm C(TWA)) were investigated, experiment B used similar but constant vapor concentrations. Olfactory- and trigeminal-mediated symptoms and intensities of odor, eye, and nasal irritations were recorded. All measures showed a dose-dependent response and peak exposure effects. In the course of the 4h exposures solely olfactory symptoms decreased. Nasal irritations remained nearly unchanged across the 4h, eye irritations slightly increased. Inter-individual differences related to the personality trait of self-reported chemical sensitivity had only minor effects on chemosensory symptoms in experiment B and no effect on intensity ratings in both experiments. Chemosensory effects seem to be amplified by exposure peaks and less adaptive than assumed.