CEN - EN 13725
Stationary source emissions - Determination of odour concentration by dynamic olfactometry and odour emission rate
|Publication Date:||1 February 2022|
|ICS Code (Other standards related to air quality):||13.040.99|
This document specifies an objective method for the determination of the odour concentration of a gaseous sample using dynamic olfactometry with human assessors. The document also specifies a method for the determination of the odour emission rate from stationary sources, in particular:
a) point sources (conveyed or ducted emissions);
b) active area sources (e.g. biofilters).
The primary application of this document is to provide a common basis for evaluation of odour emissions.
When this document is used for the determination of the odour concentration or the odour emission rate of stationary source emissions, the other relevant European Standards concerning stationary source emissions apply, in particular EN 15259 and EN ISO 16911‑1, especially when measurements have to comply with the relevant European Directives concerning industrial air emissions.
Even so, the analysis/quantificat
This document is applicable to the measurement of odour concentration of odorous gas, mixtures of odorants of defined composition and undefined mixtures of odorants in air or nitrogen, using dynamic olfactometry with a panel of human assessors being the sensor. The unit of measurement is the European odour unit per cubic metre: ouE/m3. The odour concentration is measured by determining the dilution factor required to reach the detection threshold. The odour concentration at the detection threshold is by definition 1 ouE/m3. The odour concentration is then expressed in terms of multiples of the detection threshold. The range of measurement is typically from 101 ouE/m3 to 107 ouE/m3 (including pre-dilution).
The field of application of this document includes:
1) the measurement of the mass concentration at the detection threshold of odorants in g/m3;
2) the determination of the SROM value of secondary reference odorant gas, in mol;
3) the measurement of the odour concentration of mixtures of odorants in ouE/m3;
4) the measurement of the odour emission rate from point sources and active area sources, including pre-dilution during sampling;
5) the sampling of odorous gases from emissions of high humidity and temperature (up to 200 °C);
6) the determination of effectiveness of mitigation techniques used to reduce odour emissions.
The determination of odour emissions requires measurement of gas velocity to determine the volume flow rate.
The field of application of this document does not include:
i. the measurement of odours potentially released by particles of odorous solids or droplets of odorous fluids suspended in emissions;
ii. the measuring strategy to be applied in case of variable emission rates;
iii. subjective methods for the sensory measurement of the relationship between odour stimulus and assessor response above detection threshold (perceived intensity);
iv. subjective methods for the sensory measurement of hedonic tone (or (un)pleasantness) or assessment of annoyance potential;
v. direct measurement of odour exposure in ambient air. For this measurement purpose field panel methods exist which are the subject of EN 16841‑1;
vi. direct olfactometry, including field olfactometry;
vii. static olfactometry;
viii. measurement of the odour identification (recognition) threshold;
ix. the determination of odour emission rate from volume sources, such as fugitive emissions from buildings;
x. the determination of odour emission rate from passive area sources.
Although the ultimate application of odour concentration measurement is aimed at reducing odour nuisance, the relation between emissions, dispersion, exposure and annoyance is not within the scope of this document. The relation between measured odour concentrations and odour emissions according to this standard and the occurrence of odour nuisance is highly complex. It is profoundly influenced by the atmospheric processes determining the dispersion of odours, the quality of the odour (hedonic tone) and finally by the receptor characteristics of those exposed to the odour. These receptor characteristics not only vary strongly between individuals, but also in time within one individual.