Perceived Odor, Irritation, and Health Symptoms Following Short-Term Exposure to Acetone Pamela Dalton, PhD , * Charles J. Wysocki, PhD , Michael J. Brody, BA, and Henry J. Lawley, BS The subjectivity of irritancy judgments can bias attempts to establish exposure guidelines that protect individuals from the sensory irritation produced by volatile chemicals. At low to moderate chemical concentrations, naive and occupationally exposed individuals often show considerable variation in the reported levels of perceived irritation. Such variation could result from differences in exposure history, differences in the perceived odor of a chemical, or differences in generalized response tendencies to report irritation, or response bias. Thus, experimental evaluation of sensory irritancy must dissociate sensory irritation from response bias. To this end, judgments of perceived irritation from 800 ppm acetone were obtained from acetone-exposed workers and age- and gender-matched naive controls. To assess the role of response bias during exposure to odorants, subjects were also exposed to phenylethyl alcohol (PEA), an odorant that does not produce sensory irritation. Following exposure, subjects completed a subjective symptom survey that included symptoms that have been associated with long-term solvent exposures and symptoms that have not. Acetone-exposed workers and naive controls reported large differences in the perceived intensity of odor and irritation from acetone, yet no differences in the perception of PEA. However, for both groups, the most significant factors mediating reported irritancy and health symptoms from acetone were the perceived intensity of its odor and an individual’s bias to report irritation from PEA. The perception of odor intensity and degree of response bias will differ between and within groups of exposed and naive individuals; hence, an assessment of the influence of these factors in experimental and workplace studies of chemical irritancy is warranted. Am. J. Ind. Med. 31:558–569, 1997. r 1997 Wiley-Liss, Inc. KEY WORDS: sensory irritation; odor; acetone; response bias; occupational exposure; health INTRODUCTION The highly subjective nature of perceived irritation can cause difficulties in establishing exposure guidelines to protect workers from sensory irritation produced by volatile chemicals. At sufficiently high concentrations, many com- pounds unequivocally produce irritation in the eyes and upper respiratory airways (chiefly, although not exclusively, through mediation of the trigeminal nerve [Alarie, 1966]). The intent of the guidelines is to restrict exposures to levels below which irritation occurs; hence, the exposure limits typically target low to moderate ranges of chemical concen- trations. At these levels, naive and exposed individuals often show considerable variation in the levels of perceived irritation they report. Interindividual variation in the subjective irritancy of a chemical could result from differences in exposure history if people adapt to a compound’s irritancy following repetitive exposures, just as they adapt to its odor [Cain, 1970; Cometto-Mun ˜iz and Cain, 1995; Chang and Barrow, 1984; Dalton and Wysocki, 1996]. Alternatively, variation could result from the many nonsensory factors that are thought to Monell Chemical Senses Center, Philadelphia, PA. Contract Grant sponsor: Chemical Manufacturer’s Association; Contract Grant sponsor: National Institutes of Health; Contract Grant numbers: F32 DC-00197, R01 DC-00298, and P50 DC-00214. *Correspondence to: Pamela Dalton, Ph.D., Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104. Accepted for publication 30 July 1996 AMERICAN JOURNAL OF INDUSTRIAL MEDICINE 31:558–569 (1997) r 1997 Wiley-Liss, Inc.