olfactometria

Olfactometry is a set of methods used to measure odor concentration and intensity as perceived by humans. It sits at the intersection of sensory analysis and environmental monitoring and is used to assess odors emitted by industrial facilities, wastewater treatment, landfills, agriculture, and other sources. The results help determine odor impact, support regulatory compliance, and inform mitigation strategies.

Dynamic olfactometry is the standard laboratory approach. In this method, an odor sample is presented to a panel of trained assessors through a dynamic dilution olfactometer. The device mixes the sampled air with clean air across a series of dilutions, and panelists vote whether an odor is detectable at each dilution. The test uses a dilution-to-threshold protocol, and the odor concentration of the sample is reported in odor units (OU) corresponding to the dilution at which detection occurs, often with methods such as detection threshold or recognition threshold.

Field olfactometry extends the same principle to on-site measurements using portable units. Gas chromatography-olfactometry combines instrumental separation with human detection to identify odor-active compounds and their relative contributions.

Standards and quality control: Dynamic olfactometry is standardized in many regions, with EN 13725 being a widely cited standard. Procedures cover panel selection and training, room and instrument specifications, flow control, sampling, and data processing. Results depend on panel performance, so calibration and quality assurance are essential.

Limitations and scope: Olfactometry relies on human perception, which introduces subjectivity and variability. It is time-consuming and relatively costly, but it provides a direct measure of perceived odor, complementary to instrumental chemical analysis. It plays a central role in environmental odor management and regulatory reporting.