ambient

Biofilter

A biological process where a microorganisms (bacteria or fungus) is used to remove pollutants and odour from a gaseous waste stream.  The air stream carrying teh pollutants passes through the packing bed…

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Common Air Contaminants (CACs)

Air pollutants commonly found in the atmosphere, namely carbon monoxide (CO), particulate matter (PM), nitrogen oxides (NOx), sulphur oxides (SOx), volatile organic compounds (VOCs) , ammonia (NH3) and Ground-level ozone…

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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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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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EN 13725 – YES/NO Mode

The assessor is asked to evaluate gas presented from a specific port and to indicate if an odour is perceived ( YES/NO). The assessor is aware that in some cases…

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EN 13725 – Forced Choice Mode

The assessor is presented with two or more ports, of which one presents the stimulus and the other(s) neutral gas.The location of the stimulus in consecutive presentation is randomly distributed…

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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…

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Exposure

Exposure is a combination of the amount of a pollutant in the air and the amount of time that person stays in the presence of a pollutant. Exposure determines the…

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