Odor concentration: 

The measurement of odor concentration is the most widespread method to quantify odors. It is standardized in CEN EN 13725:2003. The method is based on dilution of an odor sample to the odor threshold, at which the odor can just barely be perceived by 50 % of the test panel. The numerical value of the odor concentration is equal to the dilution factor that is necessary to reach the odor threshold. Its unit is the European Odor Unit, OU_E. Therefore, the odor concentration at the odor threshold is 1 OU_E by definition.

To establish the odor concentration, an olfactometer is used which employs a panel of test persons. A diluted odorous mixture and an odor-free gas (as a reference) are presented from sniffing ports to a group of panelists. In comparing the gases emitted from each port, the panelists are asked to report the presence of odor. The gas-diluting ratio is then decreased by a factor of 1.4 or two (i.e. the concentration is increased accordingly). The panelists are asked to repeat their judgment. This continues for a number of dilution levels. The responses of the panelists over a range of dilution settings are used to calculate the concentration of the odor in terms of European Odor Units (OU_E/m³).

The test persons must fulfill certain requirements, for example regarding their sensitivity of odor perception. The main panel calibration gas to verify this requirement used is n-Butanol.

You have the option to consider a null vertical momentum in point sources. This is usefull if you have a landfill (area source with no vertical momentum) small in comparition with the working area. You can treat it as a point source.

Estimate odor.- With this module you can estimate the odor in simple cases. You can introduce the another other odor flux quantity, if you want.

Odor units

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