Emission with sensory evaluation

When comparing the dust-borne concentrations of butyric acid and p-cresol with the odour thresholds it seems that the concentrations are too small to be relevant for an odour nuisance. However, if the dust is removed from the gas phase of the air from animal houses the odour disappears (39), (40), (14). This supports the opinion of HAMMOND et al. (40) that the odor is concentrated on the dust particles. The authors conclude from their data that the concentration of the two odorants butyric acid and p-cresol is about 4TO7 greater on an aerosol particle than it is in an equal volume of air. Thus, an aerosol particle deposited on the olfactory organ carries odour equivalent to a much greater volume of air (40). These considerations indicate that dust from animal houses should be taken into account in connection with odour emission/immission measurements not only by chemical analysis but by sensory evaluations using olfactometers without dustfilters, as well. 

Knudsen, H.N., Clausen, P.A., Wilkins, C.K. and Wolkoff, P. (2007) Sensory and chemical evaluation of odorous emissions from building products with and without linseed oil. Building and Environment, 42 (12), 4059-67. 

Two units, olf and decipol, were introduced to quantify sensory source emissions and perceived air quality [23]. With these units the so-called decipol method was developed. The decipol method comprises a panel of ten or more persons who are trained to evaluate the perceived air quality in decipol or an untrained panel of at least 50 persons [33]. A method to train a panel to evaluate perceived air quahty in decipol has been developed [34,35]. The latest research indicates, however, that this method does not evaluate the acceptability but the intensity of the air sample (for a description see Sect. 3.2). 

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