EDITOR'S NOTE: Last fall the Leopold Center Advisory Board discussed public perceptions regarding air quality in and around swine housing units. The board approved funds for a 15-month collaborative project that would begin to measure airborne contaminant concentrations and exposures in and around hoop buildings and conventional confinement facilities.
Here's a project update provided by researchers Dwaine Bundy, Amy Beatty, Wendy Powers, Peter Thorne, Peter Weyer and Terri Pearce. Work is funded by the Leopold Center, its sister institution, the Center for Health Effects of Environmental Contamination (CHEEC), and the University of Iowa Office of the Vice President for Research.
Gases such as ammonia, hydrogen sulfide and volatile organic compounds are present in all types of swine facilities. Airborne particles, also present in swine production, may include infectious and non-infectious viruses, bacteria, fungi and parasites; products of microorganisms such as endotoxins; and aeroallergens of animal, plant or microbial origin.
Interest in characterizing these exposures has brought researchers together from the ISU departments of agricultural and biosystems engineering and animal science (Bundy, Beatty and Powers) and the occupational and environmental health department at the University of Iowa (Thorne, Weyer and Pearce). The plan is to investigate and compare levels of particulate matter and gases that may occur in total slatted and deep-bedded systems.
Two central Iowa sites chosen
The project, currently in progress, measures exposures at two central Iowa pork production sites during each season of the year. One site consists of a four-room, deep pit, mechanical-assisted finisher that is naturally ventilated. The second site has three hooped buildings. Two sampling seasons have been completed so far (spring and summer), and researchers are preparing for the fall and winter sampling.
Preliminary findings show similar values in both types of systems. The concentration levels of ammonia, hydrogen sulfide and dust concentrations are lower than the accepted limits for workers. While concentrations of airborne bacteria and endotoxin also were similar, some variation was observed between levels measured either in the buildings or downwind from them.
Additional work planned
Investigators hope to collect additional samples upwind of the sites to determine if the variability is due to cropping systems and/or livestock systems.
The results of this study will help professionals understand exposures unique to agricultural settings. They also may provide guidance on health effects for farmers who work in and around either hoop structures or conventional confinement buildings.