Hedonic odor tone

Figure 8.3 Odor evaluation scales for (a) intensity (VDI 3882-1) (b) hedonic odor tone (VDI 3882-2) and (c) acceptance (Clausen etal., 1996 Clausen, 2000).

Odor intensity Hedonic odor tone Perceived air quality (decipol)... 

Blatt 2 Olfactometry - Determination of hedonic odor tone, September 1994. 

Four characteristics of odor are subject to measurement by sensory techniques intensity, detectability, character (quality), and hedonic tone (pleasantness-unpleasantness) (16). Odor intensity is the magnitude of the perceived sensation and is classified by a descriptive scale, e.g., faint-moderate-strong, or a 1-10 numerical scale. The detectability of an odor or threshold limit is not an absolute level but depends on how the odorant is present, e.g., alone or in a mixture. Odor character or qualit) is the characteristic which permits its description or classification by comparison to other odors, i.e., sweet or sour, or like that of a skunk. The last characteristic is the hedonic type, which refers to the acceptability of an odorant. For the infrequent visitor, the smell of a large commercial bread bakery may be of high intensity but pleasant. For the nearby resident, the smell may be less acceptable. 

Special problems are related to odor measurement, its quantification and to odor policy (Frechen, 2000). Odors usually consist of many different compounds of very low concentrations that may exert synergistic or antagonistic effects. Four generally accepted dimensions of odor exist which include the concentration of odorants, the intensity of odor, its character, and its hedonic tone (i. e. its pleasantness or unpleasantness). It is extremely difficult to relate conventional analytical measurements (e. g. gas chromatographic determinations or sensor array measurements with an electronic nose ) to the intensity, character, and hedonic tone of an odor perceived by the human nose. 

Odorants. Twenty-eight odorants covering a large variety of odor character notes and a broad hedonic tone range (from isovaleric acid to vanillinj were used ... 

Improvements to the Model. Since other odor notes undoubtedly influence the scores of some selected odor notes, additional variables were added to the simple regression model above on a multiple stepwise regression analysis was conducted. For each odor note, the other candidate variables were all other 29 descriptor scores, and the hedonic tone of the hedonically lowest (least pleasant or most unpleasant) and highest components. ( )... 

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