| Summary: | Odour and odorous compound measurements depend on the first analytical step: the sampling. This first step could be considered as the most important because the global results are dependent on sampling and analytical procedures but the second part (analysis) is globally more controlled. As example, olfactometric measurement procedures are well described by EN 13725 standard. But, if panel selection and all smelling parts allow limiting uncertainty for the dilution to threshold measurement, the sampling part is not as well described. Because of several approaches on sampling especially sampling from area sources, a lot of variations can be obtained by this step.
Typically, several experiments on area sources have shown that a factor 10, 100 or more can be attributed to the sampling step. In such a case, the uncertainty of the olfactometric part is negligible comparatively to the sampling part. That’s why, it is important to keep in mind that hoods or flux chambers as devices to sample on an active or a passive area respectively must be considered with strict procedures. Even if a lot of teams follow rigorously their own procedure or a regional or a national standard, the lack of international standard on this point is still a problem. Some results cannot be compared with others due to great differences on sampling.
The problem could be increased by the sample collection and storage in bags. A lot of studies showed that storage of some compounds or odours are very problematic (losses) and therefore can lead to wrong results. Of course, limitation of time storage can minimize such an impact but it’s important to consider this potential problem by taking some warranties. The present paper gives an overview on the main drawbacks linked to sampling and that affect the global response of odour measurement.
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