Using olfactometry to measure intensity and threshold dilution ratio for evaluating swine odor

Area of Science:

• Agricultural Engineering
• Environmental Science
• Sensory Science

Background:

• Odor control in swine buildings is crucial for environmental management.
• Odor threshold dilution ratio is a common metric, but its utility increases when correlated with odor intensity.
• Simultaneous measurement of these indices is needed for comprehensive odor assessment.

Purpose of the Study:

• To develop and validate a method for simultaneously measuring odor intensity and threshold dilution ratio in swine building air.
• To establish a relationship between odor intensity and threshold dilution ratio for improved odor assessment.
• To collect data for developing a mathematical model for swine odor characterization.

Main Methods:

• Utilized a dynamic forced-choice olfactometer for simultaneous measurement.
• Collected air samples from farrowing, finisher, gestation, and nursery swine rooms.
• Employed a panel of eight human evaluators to assess odor intensity.
• Calculated odor threshold dilution ratios using ASTM Standard Practice E679-91.

Main Results:

• Odor threshold dilution ratios were 333 (farrowing), 424 (finisher), 25 (gestation), and 221 (nursery).
• Odor intensities, after a 14.7-fold dilution, were 3.79 (farrowing), 3.46 (finisher), 0.48 (gestation), and 4.0 (nursery).
• Collected data were used to formulate a mathematical model.

Conclusions:

• The proposed method enables simultaneous measurement of odor intensity and threshold dilution ratio.
• This integrated approach provides a more robust assessment of swine building odors.
• The developed mathematical model can aid in optimizing odor control strategies for swine facilities.