A Multi-Year Field Olfactometry Study Near a Concentrated Animal Feeding Operation

ABSTRACTThis study developed and tested a protocol for monitoring odors near a Concentrated Animal Feeding Operation (CAFO). The Nasal Ranger, a portable field olfactometry instrument, was used by a panel of trained individuals to conduct the monitoring near a swine CAFO. Monitors were selected based on olfactory sensitivity, scheduling availability, and lack of association with the CAFO or residential neighbors of the CAFO. Monitors were trained to use the Nasal Ranger, collect and record weather data, and characterize any odors detected. Data were collected over a 3-year period (2007-2009) for approximately 9 months each year. The data recorded included odor intensity, a description of the odor, date and time of the reading, and weather conditions.Of more than 50,000 readings, forty-one (0.1%) odor readings had a dilution to threshold ratio (D/T) of ≥ 7:1 and were attributed to hog manure. The frequency of odor readings attributed to hog manure with D/T ≥7:1 was found to negatively correlate with log wind speed and positively correlate with wind from the direction of the farm. Other meteorological variables (temperature, precipitation, cloud cover) and time of day did not influence the frequency.IMPLICATIONSThe use of a portable field olfactometry instrument can provide an assessment of the intensity, frequency and duration of odor in real time. Along with descriptors of the odors being detected, such data can provide a basis for the evaluation of odor complaints.