Air Quality Management Expert and Consultant

R & D

Olfactory disagreement has become one of the most important well-being and comfort factor. Some methods exist to evaluate olfactory gene, but they are based on a posterior control of the feeling of a limited number of persons. Furthermore, odor acceptability is rarely used to determine the hazardous potential of fragrance sources.

R et D

Olentica has developed and offer a new method to evaluate odours acceptability. After having determined odour concentration, in accordance with EN 13725 standard, it consists in measuring acceptability level at a concentration close to the previously found threshold. A jury determined this threshold when all of its members have detected the odour. An extrapolation of regression line at dilution zero allow to obtain the acceptability of the sample at its original concentration. Nuisance potential of the effluent can then be calculated by multiplying odour concentration and it’s acceptability.

This evaluation is realized on the same sample, by the same olfactometer and the same jury (six members as in the EN 13725 standard) that has been used during the previous stage.

Several steps of the method are described and illustrated below:

  1. Determination of the dilution level at which all jury members distinguish the smell.
  2. Evaluation of the acceptability of the smell at this level of dilution, on a scale from -5 to +5 (-5 = very unpleasant odour, 0 = neutral odour, + very pleasant odour).
  3. Repetition of step 2 with three lower dilution levels.
  4. Calculation of median acceptability for each dilution.
  5. Tracing the acceptability as a function of dilution levels.
  6. Extrapolation of regression line with no dilution to obtain the level of acceptability of the sample tested on an open scale (- ∞ to + ∞).

As for the VDI 3882-2 standard, this method avoids to expose jury members to high intensity odour levels and potentially toxic concentrations.