Publication in the journal Gefahrstoffe / Reinhaltung der Luft - Uncertainty of odour emission measurements

Expert article by Dipl.-Geol. Boris Zimmermann, Branch Office Gelsenkirchen, on „Study on an active area source“ in the professional journal Gefahrstoffe/Reinhaltung der Luft.

The assessment of the measurement uncertainty plays an important role when the validity of emission measurements results is evaluated. In the standard VDI 3884 Part 1, for olfactory measurements a procedure is described how the measurement uncertainty can be determined for n-butanol based on the laboratory’s current daily standard deviation. Within the scope of an emission measurement series at an area source, we even exceeded the requirements of VDI 3884 Part 1 and tried to assess effects of measurement uncertainty in the course of the evaluation and in connection with sampling or by assessing the total measurement uncertainty for the evaluation. Concerning the ex-panded measurement uncertainty resulting from the olfactometrical analysis, it can be assumed that the uncertainty can be determined on a daily basis and typical of the respective laboratory, based on the repeatability determined by reference odorants. By choosing a narrowing on the standard requirements beyond selection of panel members, the measurement uncertainty calculated according to VDI 3884 Part 1 can even be reduced to a value below 1 dBod. It is, however doubtful whether such low measurement uncertainties for olfactometry can include the measurement uncertainties for sampling which is expected indirect in the VDI 3884 Part 1 on the basis of studies. Concerning the contributions to measurement uncertainty due to sampling, the results of the present evaluation indicate that at least for complex source configurations and probably also exhaust gas boundary conditions, the type of sampling and the applied measurement equipment can contribute significantly to an expanded measurement uncertainty.

Odours – Measurement, Prediction, Advice

FrontPage Journal "Gefahrstoffe - Reinhaltung der Luft" issue October 2015

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