scenroid

Active sources

Have a defined gas flow emitted from source.  Example includes a biofilter or aerated pond.  According to VDI3880, an active source is defined by an average flow velocity of 30m/h…

Read more

Anosmia

Anosmia is the temporary or permanent complete loss of ability to perceive odour. Temporary anosmia can be caused by infection or nasal blockage. Permanent anosmia may be due to damage…

Read more

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…

Read more

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…

Read more

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…

Read more

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…

Read more

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…

Read more

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…

Read more

Electronic Nose

An electronic nose (e-nose) uses a sensor array that reacts to air pollutants by leaving behind a ‘fingerprint’ that can be attributed to an odour.  It is essentially composed of a sample…

Read more

EN13725

In Europe, dynamic olfactometry, is described in detail by the European standard EN 13725. This standard was last released in 2003 and is currently under review for revision. Key elements of…

Read more