Upper airway irritation, odor perception and health risk due to airborne chemicals

Chemosensory irritation associated with the manufacture and use of volatile materials has been a public and employee health concern for many years. Because odor properties can often be detected at much lower concentrations than those capable of eliciting upper respiratory tract irritation, confusion between odor and irritation coupled with variability in odor sensitivity and response can produce significant obstacles for evaluating the potential for adverse effects or annoyance from worker and community exposures. Although rigorous research methods have been developed to accurately quantify chemosensory irritation in human evaluations, several important considerations should be included in the design and interpretation of such studies. Specifically, research studies evaluating chemosensory irritation from volatile materials should be capable of (1) distinguishing between the annoyance or concern elicited by odor sensation and that elicited by true sensory irritation, (2) evaluating exposure-related factors that affect odor or irritancy responses, and (3) separating true adverse health effects from those mediated via psychosocial factors. Objective measures of upper respiratory tract irritation onset obtained in conjunction with subjective reports can lend valuable input to the decision process for determining occupational exposure limits. Subjective reports of irritation at low levels that cannot be reconciled with objective measures should prompt a careful investigation into the other factors (e.g. cognitive or emotional) that may be modulating the sensory response. Distinguishing between the exposure that elicits local effects of sensory irritation in the upper respiratory tract and the exposure that elicits self-reports of irritation is a key component in establishing occupational exposure limits that are protective of exposed workers.