The draft of the German standard VDI 3940 Part 6:2025-07 was published in July this year. This text addresses the determination of disgusting and nauseating odours. This standard is currently in draft stage, accepting comments from interested parties.
During the last biennial conference of the Association of German Engineers (VDI)on odour management in the environment, held in Salzburg, several interesting presentations took place. One of them moved away from the concept of odour as being “only an annoyance”. In fact, this presentation, given by Dr Kirsten Sucker, addressed the question of whether an odour “merely” constitutes a considerable nuisance or whether it is so disgusting and nauseating that it should be classified as a harmful effect on the environment. But what exactly is the difference and how can this be determined?
In Germany, there are odour limits based on odour hours and certain frequencies as set out in the Air Quality Regulation TA Luft, specifically in Annex 7. However, that same annex, in Nr. 5 “Assessment on a case-by-case basis”, specifies in its paragraph c that a comparison with these odour limits is not sufficient if “harmful environmental effects" occur despite compliance with the ambient air values (for example, odours causing disgust and nausea)”. In other words, in the case of such odours, the “nature” and no longer the “extent or duration” of the ambient air concentrations addressed in Article 3, paragraph 1 of the Air Quality Act itself, known as the BImSchG (the Germans do love their acronyms), comes into play .
And what does this article say? The paragraph reads: “Harmful effects on the environment within the meaning of this Act are ambient air concentrations which, by their nature, extent or duration, are capable of causing dangers, considerable disadvantages or considerable nuisances to the general public or to the neighbourhood.”
This definition sets the threshold for considering an ambient air odour concentration as “schädlich” (harmful), covering not only serious risks but also significant nuisances, and serves as the basis for all prevention and authorisation obligations under the BImSchG.
If there is suspicion that odours perceived by a population are disgusting and nauseating, the competent authority must undertake a more thorough control effort than the one described in TA Luft. The standard VDI 3940 Part 6:2025-07 Determination of disgusting and nauseating odours has been designed to assist competent authorities is now open for comments in its draft stage.
For odour managers who wish to learn a bit more, this standard defines a critical disgust potential (EPkrit ≥ 22.125), beyond which the odour is no longer assessed and compared to odour limit values. The reason is that immediate health risks may arise from disgusting odours. In this case, it is assumed that there is an immediate health hazard rather than merely a considerable nuisance (which also affects health, btw), making prompt action necessary.
To calculate the critical disgust potential, a weighting is made of the measurements of intensity (according to the standards VDI 3882 Part 1 and VDI 3940 Part 3), hedonic tone (VDI 3882 Part 2) and odour annoyance (VDI 3883 Part 1). In addition, the potential disgust effect is determined through two yes/no questions, namely whether physical symptoms (nausea, increased salivation, vomiting) occur or are perceived, and whether the odour is perceived as “disgusting”.
To learn a bit more, the ideal option is to purchase the standard VDI 3940 part 6, although I would wait for the final version to be published, unless, of course, you are in a hurry.
If you find this article interesting, you might also be interested in these articles:
- Last Friday the GOAA became a new odour regulation in Germany
- The German Law in Air Quality will incorporate ambient air limit values
- Workshop on the forecoming changes regarding odours in the new German regulation on air quality
- The new regulation on Air Quality of Germany came into force in December
- A Successful 11th VDI Conference Odours in the Environment
