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Delayed Olfactometry

A time-lag between sampling and measuring of odour concentration where the odour sample is preserved in an appropriate container (odour-netutral material). Can also be referred to as static sampling. Delayed…

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Detection threshold (DT)

Detection threshold is essentially the minimum amount of odorant that can be perceived (smelled).  This minimum amount represents the odour concentration and is a measurement of 1 OU (1 odour…

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Diffuse sources

A source having a specified area or volume that does not have a defined air flow.  Examples include waste dumps, compost piles, sedimentation tank.  An example that is not a…

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Dilution factor

A ratio of diluting neutral gas to odourous sample gas.  According to ASTM E679, this is a ratio of diluting gas to the odour sample.  According to the EN13725, this…

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Direct Olfactometry

Measurement of odour without a time lag between sampling and analysis. The time lag between sampling and analysis according to the EN 13725 is 30hours and according to the VDI…

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Downwind

The relative location of an observer with respect to a source of odour emission.  The direction of wind movement would first cross the odour source followed by the observer.  An…

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Dynamic dilution

Mixing of odourous gas and odour-neutral air measured by flow rate. The consistent introduction of odour-free or odour-neutral air to a concentrated amount of an odourous gas allows for an…

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Dynamic Dilution Olfactometry

Dynamic Dilution Olfactometry  is based on “dilution to threshold” of a gas sample with multiple components. Odour threshold is a commonly used term. It is the minimum concentration detectable or…

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Dynamic olfactometer

A device which mixes neutral gas (odourless air) with odourous gas in specified ratio by flowrate and delivers mixture to an outlet for analysis.  The analysis involves a selected panel…

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