Modeling the relationship between detection threshold and intensity of swine odors

Odor detection threshold and intensity were measured from swine buildings and manure storages in Minnesota during 1998 and 1999. Detection thresholds were obtained with a triangular forced choice olfactometer. Intensity values were obtained by comparing the full strength sample to a six-level reference scale of 1-butanol in water. The Weber-Fechner, Stevens, and Beidler models were investigated to determine which best described the relationship between detection threshold and intensity. The Weber-Fechner logarithmic model provided the best form to describe the relationship between odor detection threshold and intensity from the swine buildings. For odor from manure storage, all three models were similar with the Weber-Fechner model indicating a slightly better fit. There were significant differences between the slope parameters from the building emission data and the manure storage data.