Last year, a total of 40 laboratories from 14 different countries participated in an Interlaboratory Comparison (ILC)  to check proficiency according to European standard EN 13725/2003. However this ILC did not study the influence of  “Sampling” on the overall uncertainty.  Taking an odour sample is another parameter to take into account in the estimation of the overall uncertainty of a lab, and the Hessian Agency for the Environment and Geology (HLUG) organized a regular test with over 15 labs for the very first time. From the 27th to the 28th of October,  the first ILC that considered not only analysis, but also stack sampling was carried out.

   Interlaboratory comparisons (ILCs) also called Proficiency Tests are organised to check the ability of laboratories to deliver accurate testing results to their customers. 

   The existing standard EN 13725, first published in 2003, requires revision. The 9^th meeting of the group that deals with the revision of the EN 13725 just took place in Antwerp, Belgium. The members of the Task Group that is dealing with the calculation of the uncertainty agreed that n-butanol is probably not representative for all environmental odours. In addition, n-butanol does not necessarily describe the sense of smell for a panelist very well. The new Standard EN 13725 will define a new procedure to design and test any new reference odorant. Is this the end of n-butanol as a reference material for olfactometry?

   The odour concentration of an odorous gas sample is determined by presenting a panel of selected and screened human subjects with that sample, varying the concentration by diluting with neutral gas, in order to determine the dilution factor at the 50 % detection threshold. At that dilution factor the odour concentration is 1 ou_E/m³ by definition.