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Published on: July 19, 2018
Predictions by the Odor From Feedlots, Setback Estimation Tool (OFFSET) compared with observations by neighborhood
Sven A Nimmermark1, Larry D Jacobson, David R Schmidt
1Department of Agricultural Biosystems and Technology, Swedish University of Agricultural Sciences, Alnarp, Sweden.
Journal of the Air & Waste Management Association (1995)
|November 2, 2005
Summary
The Odor From Feedlots, Setback Estimation Tool (OFFSET) generally predicts adequate separation distances for livestock farms. However, some farms may require greater distances for specific annoyance-free frequencies, indicating a need for model refinement.
Area of Science:
- Environmental Science
- Agricultural Engineering
- Atmospheric Science
Background:
- Livestock farms can generate odors affecting nearby communities.
- Accurate prediction of odor dispersion is crucial for land-use planning and mitigating community impact.
- The Odor From Feedlots, Setback Estimation Tool (OFFSET) was developed to estimate necessary separation distances.
Purpose of the Study:
- To evaluate the accuracy of the Odor From Feedlots, Setback Estimation Tool (OFFSET) in predicting odor intensities.
- To compare predicted separation distances with observed odor annoyance levels at residential sites near livestock farms.
Main Methods:
- Conducted a comparative study of predicted versus observed odor intensities.
- Utilized neighborhood monitors to collect odor intensity data at 20 residences across five Minnesota counties.
- Analyzed data to assess the performance of the OFFSET model for various annoyance-free frequency thresholds.
Main Results:
- OFFSET-predicted separation distances were deemed sufficient for high annoyance-free frequencies (99-97%).
- For lower frequencies (94-91%), predicted distances were adequate for some farms but insufficient for others.
- Significant differences between predicted and observed odor intensities were found at several sites, with considerable discrepancies at three locations.
Conclusions:
- The Odor From Feedlots, Setback Estimation Tool (OFFSET) provides a reasonable estimate of average odor emissions but may require improvements for specific source types.
- Factors such as emission fluctuations, wind variability, topography, and background odors can contribute to discrepancies between predicted and observed odor impacts.
- Further refinement of the OFFSET model is recommended to enhance its accuracy in predicting odor annoyance across diverse farm and environmental conditions.
