In the latest issue of the Journal of Occupational and Environmental Hygiene there is an article on bacterial plumes that emanate from the air surrounding swine confinement operations (no link yet). The researchers measured bacteria in the air plume at upwind and downwind locations around confined animal feeding operations (CAFOs).
The data show a marked increase in bacterial CFUs/m3 inside the facility (18,132 CFU/m3 average) versus upwind (63 CFU/m3 average) and a steady downwind decrease out to approximately 150 m. Staphylococcus aureus was found to account for 76% of the organisms recovered.
Attempts to litigate against CAFOs based on the nuisance of unpleasant odors have had mixed success in the courts. Perhaps cases based on excess bacterial loads in the air would be more successful.