Odor and chemesthesis from exposures to glutaraldehyde vapor

Objectives Assessment of olfactory and chemesthetic sensitivity (feel, sensory irritation) to vapor of glutaraldehyde in young adult females. For chemesthetic sensitivity, assessment included the variable of duration, with focus on whether concentrations initially too low to evoke feel in the eye or upper airway might do so in exposures up to 15 min. Methods Experiment 1 probed sensitivity with forced-choice testing of detection over ranges of concentrations appropriate to three endpoints: odor, feel in the eye, and feel in the nose. A subject participated in hours of testing per endpoint to yield enough data to erect a psychometric (concentration-response) function. Exposure in Experiment 1 entailed use of a vapor-delivery system that stimulated sites of interest separately. Exposure in Experiment 2 occurred in the ambient environment of a chamber, with the sites stimulated simultaneously. In that case, subjects rated confidence by the minute that they felt the presence of vapor in the eyes, nose, and throat during exposures of 15 minutes to 35, 50, 75, and 100 ppb, a blank, and an odor control of mild heptane. Results In Experiment 1, the typical subject achieved 50% detection (threshold) of odor at 0.3 ppb. The typical subject achieved 50% detection of feel in the eye and nose at 390 and 470 ppb, respectively. Psychometric functions for feel showed much sharper dependence on concentration than those for odor. In Experiment 2, confidence in detection of feel migrated progressively away from no-with certainty toward the zone of uncertainty, with bigger change when the exposures contained any glutaraldehyde. The ratings of confidence failed, however, to show distinguish among these concentrations. Conclusions Glutaraldehyde has much higher odor potency than previously thought. Its green-apple odor should signal presence of the vapor at levels more than a 100-fold below any that might evoke sensory irritation in brief exposures. Exposures that start decidedly below irritating (100 ppb and below) seem unlikely to turn irritating over time. Although the effects from these concentrations differentiated themselves from those of air and an odor control, they exhibited none of the concentration dependence seen for sensations of feel. They seemed likely driven by the penetrating odor of glutaraldehyde.