The revised Dutch Odour Standard NTA 9065 was just published

   The Dutch standard NTA 9065 on Odour Measurement and Calculation was first published in 2012. Now 11 years later, the updated version of this standard has been published. The text provides requirements and instructions for the standard procedure for conducting odour testing in the Netherlands.

   This standard has been divided into 2 parts: The NTA 9065-1 'Design, execution and reporting of odour studies' and NTA 9065-2 'Sampling and analysis', which is an update of the recently approved EN 13725:2022 with further info for practitioners in the Netherlands.

   The standard was submitted for public information three years ago, and we have already written about it. We mentioned several essential points not in the previous EN 13725:2003 on that occasion. How many of these points are already included in the new EN 13725:2022?

    Let's have a look:

 Relevant changes of NTA 9065:2023 Old EN 13725:2003  EN 13725:2022
 At least three samples must be taken per source and the flow rate must be measured also three times. Not specified Recommended but not compulsory
 Sampling time to withdraw a sample is at least 30 min. Not specified Recommended but not compulsory
 When changing the source to be sampled, the sampling train must be effectively cleaned or replaced by demonstrably clean parts. Not specified  Compulsory
 Field blanks should be taken to check if the sampling train is odour-free.  Not specified  Compulsory
 Maximum allowed odour concentration of the field blank is 80 ouE/m3  Not specified  Not specified. There is a note with a range of blanks.
 Sampling hoods are no longer valid to sample active area sources. Either you cover everything up and sample, or you cover partially at least 50% of the total area.  Not specified Using a sampling hood is still an alternative
 Only the forced choice method is allowed for analysis  Allowed forced-choice and tes/no mode  Allowed forced-choice and tes/no mode
A minimum of 6 panel members are required for olfactometric analysis. A minimum of 4 panel members A minimum of 4 panel members
A factor 2 is taken as permissible measurement uncertainty. Not specified A factor 2 is taken as permissible measurement uncertainty.
Labs are required participate in proficiency tests annually. Recommended but not specified any frequency of testing. Recommended but not specified any frequency of testing.
Design criteria for Wind tunnel are specified in an informative annex. As this annex is informative, no specific design for wind tunnels is mandatory. Not specified any special design  Not specified any special design

   An important aspect to consider is that total time to sample a point source is over 4 hours per source considering setting equipments, flushing bags, 30 min sampling time, taking triplicates, measuring three times flow, cleaning or replacing equipment and getting a field blank.


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Carlos Nietzsche Diaz Jimenez's Avatar

Carlos Nietzsche Diaz Jimenez

Carlos is the editor-chief of and has been in the odour world since 2001. Since then, Carlos has attended over 90 conferences in odour management, both national and international and authored a few papers on the subject. He has also organized a few international meetings and courses. Carlos owns a small company named Ambiente et Odora (AEO). He spends his free time with his wife and his twins, Laura and Daniel, and of course, writing on

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