SENSORY REACTIONS OF NASAL PUNGENCY AND ODOR TO VOLATILE ORGANIC-COMPOUNDS - THE ALKYLBENZENES

Research assessed the independent contribution of the trigeminal and o lfactory nerves to the detection of airborne chemicals by measuring na sal detection thresholds in subjects clinically diagnosed as lacking a functional sense of smell (anosmics) and in matched normal controls ( normosmics). Anosmics can provide only odor-unbiased pungency threshol ds. Normosmics provided odor thresholds. Stimuli included homologous a lkylbenzenes (from toluene to octylbenzene), chlorobenzene, 1-octene, and 1-octyne. As seen before with homologous alcohols, acetates, and k etones, both types of threshold declined with increasing carbon chain length. Anosmics failed to defect alkylbenzenes above propylbenzene. T he strong linear correlation between pungency thresholds and saturated vapor concentration for all tested compounds, as a whole, and the con stancy of pungency thresholds expressed as percent of vapor saturation , suggests that nasal pungency from these substances relies heavily on a broadly tuned physicochemical interaction with a susceptible biopha se within the cell membrane. Through such a nonspecific mechanism, low , subthreshold levels of a wide variety of volatile organic compounds of low reactivity-as found in many polluted indoor spaces-could add th eir sensory impact to precipitate noticeable sensory irritation.