The correlation and prediction of VOC thresholds for nasal pungency, eye irritation and odour in humans

A general equation set up for the study of transport properties has been applied to volatile organic compound (VOC) nasal pungency and eye irritation thresholds, as log (1/NPT) and log (1/EIT). The equation accounts for 93-95% of the total effect, thus suggesting that the main step is transport of the VOC from the gas phase to a receptor phase. In the case of odour thresholds the general equation accounts for only 77% of the total effect. A modified equation incorporates a factor for aliphatic aldehydes and carboxylic acids, and a general size effect that depends on the VOC maximum length. The size effect is important in that it leads to a cut-off effect that greatly reduces the potency of higher homologues. The various equations can all be used to predict chemosensory thresholds for thousands of VOCs. Copyright (C) 2002 S, Karger AG, Basel.