Of all environmental nuisances, odor represents the second-greatest source of complaints after noise. In the case of complaints relating to air quality, odors often constitute over 70% of the total. Note too that the scientific literature on the subject describes exposure to odors as a possible trigger for psycho-somatic effects and health problems.

A firm consensus has appeared in the scientific community about the impossibility of determining the minimum level of sensory perception of an odor from chemical analyses. Only olfactometry allows us to deduce the odor level sensed in the case of complex mixtures of odors, such as collected during field sampling. Odor measurement methods by dynamic dilution olfactometry are standardized methods which allow the characterization of all aspects of an odor (intensity, concentration, hedonic nature, quality).

The methodology of an odor-impact study is designed to assess the impact of odor emissions in the study area, using emission characterization and atmospheric dispersion modeling. This is the recommended protocol for producing an objective technical assessment of the impact of a project.

Many professionals take samples or run discontinuous odor measurements in ambient air for various purposes. The following note is a concise presentation of the scientific, technical and instrumental aspects of discontinuous measurement of odors in ambient air for the purpose of characterizing the odor impact.
To read the technical note

Both characterization via chemical analysis, and characterization via sensory or olfactometric methods offer their own advantages and drawbacks.
The principal advantage of the olfactometry approach stems from the direct correlation between odor and the sensitivity of the detector being used, i.e. the human nose. To read the technical note