Development of the OFFSET model for determination of odor-annoyance-free setback distances from animal production sites. I. Review and experiment

The objective of the study was to develop a science-based model, OFFSET (Odor from Feedlot - Setback Estimation Tool), to establish setback distances from animal production sites based on the use of an air dispersion model (INPUFF-2) and the actual odor emission data from these sites. Extensive research was conducted to obtain representative odor emissions from various animal facilities and to evaluate the air dispersion model. Odor emissions were measured from 280 animal buildings and manure storage units on 85 farms in Minnesota during 1998 to 2001. The geometric means of the odor emission rates for each type of odor source were obtained to represent odor emissions of that source. The efficiencies of some odor control technologies were summarized. The air dispersion model was evaluated for short-distance (