In recent years, confined animal feeding operations (CAFOs) have changed dramatically. While the number of operations has dropped, the size of individual CAFOs has increased tremendously. Along with this change in operating model have come numerous issues affecting human and animal health and comfort. One of the most visible of these is the issue of air quality. Air pollution from a CAFO is comprised of dust and gaseous emissions that disperse in the down-wind direction. While there are numerous regulations dealing with pollution components that affect health (i.e. PM-10 dust and hydrogen sulfide), there is no regulation of other components that can have severe effects on quality of life. Chief among these is odor. While odors are not federally regulated, many local governmental divisions (county boards, etc) consider odor-related issues when granting operating permits. It is up to the scientific and engineering community to provide these entities with a sound, equitable, and defensible basis for making decisions.

To address these challenges, we will discuss recent work at the University of Nebraska designed to measure and model the concentrations and dispersions of odorous components from CAFOs. We are evaluating two Gaussian dispersion models for predicting down-wind and cross-wind concentrations. We have also explored the use of these models (in the back-calculation mode) to determine source strengths from area (non-point) odor sources. In conjunction with this, we will also discuss a relatively new air sampling technique (Solid Phase Micro-Extraction or SPME) that we hope will provide improved sensitivity and field productivity.