The working group CEN/TC264/WG2 ‘Odours’ has prepared a draft European Standard for olfactometry for the CEN (Comite europeen de normalisation). Before enquiry and voting, this method had to be validated and this process, an International Olfactometry Comparison (ICO), was realized by 19 European Laboratories (who had been vetted) in the summer 1996. The odour source used for the comparisons was n-butanol at concentrations ranging from 15 to 400 ppm/v equivalent to 375 to 10000 oue/m3 (European odour units). The Dutch laboratories (8) also tested a complex environmental odour at the demand of the Netherlands Council for Accreditation/Netherlands Calibration Organization (NKO). For n-butanol, 5 of the 14 audit-compliant laboratories met the quality criteria on accuracy and repeatability and for the tests done with the complex odour in Dutch laboratories, 2 out of 6 attained both criteria. Considering these results, the quality criteria set in the draft European Standard are attainable and the document will be forwarded by CEN/TC264/WG2 ‘Odours’ for public enquiry among CEN organization members at the end of 1997 who should vote on it in 1998.
Even when meeting accreditation requirements, odour concentration measurement in the Netherlands is now 2/3 lower in cost compare to the 1980 level even with no consideration for inflation.

The results obtained in the ICO gave CEN/TC264/WG2 ‘Odours’ enough confidence to recommend the draft European Standard for olfactometry to the CEN for voting. Strict methods and procedures have to be followed to meet the quality criteria and as stated in the proceeding, ongoing internal quality control in a laboratory is making a difference in meeting those criteria. As mentioned in another conference, the panel selection is very important because it has a direct impact on the results.