A Screening Tool for Selection of Field Odor Assessors

Abstract

ABSTRACT Field odor assessors are required to rate or describe several odor parameters, such as intensity, duration, offensiveness, and character. Ideally, their assessments should reflect the average odor perception of a specific community. The authors developed a three-part screening test for recruiting odor assessors: (1) distinguishing between different odorants by means of a triangular forced-choice test; (2) evaluating odor intensity; and (3) describing hedonic tone and odor character. Grading was based on two criteria: correctly answering the relevant parts of the test, and evaluation of odor parameters relative to the entire tested population. The latter involved grading each tested individual according to the similarity of their score to the average result of 179 tested individuals, comprising 48% women and 52% men whose age and residence distributions were identical between women and men (except for the oldest group). To exclude relatively less sensitive individuals who showed poor ability to distinguish between different odorants and various odor intensities, and/or provided atypical description (or rating) of odor intensity, character, and offensiveness, it was suggested that only individuals whose final score was within the upper 75% (final score ≥80.75) would be qualified as odor assessors. According to this criterion, 73.8% of men and 78.6% of women passed the test. Among urban and rural dwellers, 77.4% and 67.4%, respectively, were qualified. Pass rate clearly diminished with increasing age: from 89.3% at 21–30 years to 54.6% at 61–70 years. This screening tool is recommended by the Israel Ministry of Environmental Protection for selection of field odor assessors to serve the general community and regulatory authorities. IMPLICATIONS A new screening tool for selection of field odor assessors is presented. A unique feature of this tool lies in its grading procedure, which is based on two desired qualities: (1) distinguishing between different odorants and various odor intensities; and (2) describing (or rating) odor intensity, offensiveness, and character in a way that best reflects that of the average residential population. Use of this screening tool for selection of field odor assessors to serve the general community, regulatory agencies, and other environmental authorities seems practicable, and it was proposed to Israel's Ministry of Environmental Protection as a national standard tool. The test is very simple to perform and does not need any special laboratory; however, because of expected cultural variations in odor perception, local calibration of the test is recommended.