Intensity of odor and sensory irritation as a function of hexanal concentration and interpresentation intervals: an exploratory study.

Hexanal is a suspected irritant in indoor air. Free-number magnitude estimation was used to measure intensity of odor and sensory irritation of two test concentrations (64 or 178 ppb) as a function of five concentrations and four interpresentation intervals. 9 of 12 participants (6 men, 6 women, ages 20-30 years) were able to detect the odor and report sensory irritation. The method of constant stimuli was applied to calculate the absolute thresholds of hexanal, which were 25 ppb for odor and 281 ppb for sensory irritation. Well-fitting power functions had a higher exponent for sensory-irritation intensity than for odor intensity (0.71 vs 0.66). A statistically significant effect on odor intensity was found for the concentration of presentations preceding the test stimuli and an interaction between concentrations and interpresentation intervals; however, sensory irritation was experienced to last longer than the odor of the same concentration.