Perceived odor and irritation of isopropanol: a comparison between naïve controls and occupationally exposed workers

Abstract

The results indicate that current exposure guidelines would be adequately protective of the acute adverse effect of nasal sensory irritation, as operationally defined by the intra-nasal lateralization threshold. Exposures to higher concentrations should perhaps be evaluated on the basis of existing knowledge about systemic, rather than local (e.g., irritation), toxic effects. IPA appears to be a weak sensory irritant and occupational exposure to IPA appears to elicit small changes in sensitivity that do not generalize to other odorants (e.g., PEA and 1-butanol) and are likely to be reversible.

Characteristic component odors emerge from mixtures after selective adaptation

“…Studies of anosmic humans [12,17] have shown that phenethyl alcohol and vanillin mostly activate the olfactory nerve, CN I; but isopropyl alcohol [60] and l-menthol, like many olfactory stimuli, also activate the trigeminal nerve, CN V. Compared to extra controls (control bars at left of bars for extra stimuli in Fig. 4), correct identification of characteristic odors of extra compounds, with or without trigeminal epitope, increased by 18 % when added to the adapted mix.…”

Setting occupational exposure limits in humans: contributions from the field of experimental psychology

“…A few examples of ODTs and LTs obtained in the lab comparing previously exposed workers to subjects previously unexposed to a certain compound: (geometric) mean odor and irritation thresholds of 50 ppm and 15,682 ppm, respectively, for acetone were obtained by Wysocki et al (1997); 10 ppm and 8,874 ppm, respectively, for methyl iso-butyl ketone (MIBK) by Dalton et al (2000) and 11 ppm and 3,361 ppm, respectively, for isopropyl alcohol by Smeets and Dalton (2002).…”

“…This level would be low enough to protect the majority of people as they would not yet perceive irritation at that particular level. For example, in Smeets and Dalton (2002) the fifth percentile of LTs for IPA based on a sample of 52 subjects was determined at 400 ppm, which is equivalent to the threshold limit value in the USA, which is 400 ppm (ACGIH 1998). For MIBK, Dalton et al (2000) reported a fifth percentile of 1,802 ppm, and for acetone, 2,694 ppm, both of which are higher than their current allowable exposures and confirm that the current OEL based on irritation would be sufficiently protective.…”

“…Another approach to studying the organism's response to airborne irritants is that of whole body exposures in which the participant receives an ambient exposure to a volatile chemical in a controlled environment. Numerous endpoints can be monitored over the duration of the exposure, typically involving ratings of odor and irritation intensity and health symptoms at suprathreshold concentrations, and physiological and cytological endpoints related to irritancy of in most cases the upper respiratory pathways and eyes Smeets et al 2002;Van Thriel et al 2005). This approach has several advantages over the LT method just described, as it allows for the assessment of effects due to adaptation, habituation or perhaps even sensitization of the trigeminal and olfactory systems over the course of time, which may alter the subject's reactivity.…”

Trigeminal Chemesthesis

“…Chamber studies testing formaldehyde at various fixed concentrations revealed that perceived irritation (nasal and ocular) increased with time during a 30-min exposure (Cain et al, 1986). In realistic daily home or occupational exposures to a chemical vapor that might be causing mild irritation, the nasal chemesthetic threshold for that chemical increases, revealing desensitization, but the effect does not appear to generalize to other irritants (Dalton et al, 2006;Smeets and Dalton, 2002;Wysocki et al, 1997). Exposures of two to three hours to mixtures of VOCs (Hudnell et al, 1992) and to the complex stimulus environmental tobacco smoke (Cain et al, 1987) revealed that the perceived intensity of chemesthesis clearly increases with time.…”