Emission and Odor Study on a Swine Farm

September 2001


Lynn and Pat Harrison


Elk Mound, Dunn County, WI


Corn, Soybeans, Pork

Research Opportunities

This farm was chosen to represent confinement swine and row crop operations in Wisconsin.

The Harrison Farm grows two years of corn followed by one year of soybeans on 800 acres of sandy loam cropland. Corn and soybeans are planted using a no-till establishment system to help with soil fertility and runoff control. Corn is harvested as grain and fed to finish hogs. Soybeans are sold as a cash crop.

The farm has 5 individual swine finishing barns managed at 3 non-adjoining properties. Full capacity for the 5 barns is 3,900 head. Barns are emptied and refilled 2.6 times each year. Liquid swine manure is injection applied to cropland at 3,000 gallons per acre.

Air quality is an environmental issue facing Wisconsin livestock producers as State agencies begin exploring how livestock facility emissions and odors are impacting air quality. Producers may soon be faced with regulatory pressure to manage livestock facilities and feedlots to comply with air quality standards.

Ammonia is emitted from livestock housing facilities, manure storage areas, and manure/fertilizer application areas. Ammonia (N gas) that is emitted to the atmosphere from agricultural areas either remains in the air as particulate haze or gets re-deposited back to land and water. Ammonia emission concerns include:1) atmospheric particulates that cause haze and stimulate human respiratory health issues; and 2) ecosystem nitrogen fertilization where extra nitrogen causes plant species to shift from native species to grassy, soil acidification, and adds extra nitrogen into the Mississippi River - Gulf of Mexico surface water system where a hypoxia zone has developed.

Hydrogen sulfide is a product of anaerobic decomposition of organic matter. Liquid livestock manure storage areas generate hydrogen sulfide. Hydrogen sulfide is toxic and causes human and animal health concerns. Exposure to hydrogen sulfide causes dizziness, headache, nausea @ 50 ppm; and death from respiratory paralysis @ 1,000 ppm. The OSHA indoor workplace standard for hydrogen sulfide is 10 ppm for an 8 hour day. Periodically, farm workers are overcome by manure pit gas and die as a result of hydrogen sulfide.

Odor from livestock facilities arise from a mixture of different gases, existing at low concentrations. The actual odor can be from any combination of manure, dust, decaying feed, and other material. Odors evoke a wide range of physical and emotional reactions, both positive and negative. Many livestock facility odors are identified by the surrounding neighborhood as negative.

Monitoring in Place:

In June of 2004, the University of Wisconsin Discovery Farms Program coordniated air quality monitoring for ammonia, hydrogen sulfide and odor on the Harrison farm. This was a cooperative effort with technical monitoring conducted by Baumgartner Environics, Olivia, MN; WI DNR; and on-site assistance provided by University of Wisconsin Discovery Farms staff.

Air quality measurements and samples were gathered from the 5 swine finishing barns. Barns were total confinement with mechanical ventilation and manure storage pits below slotted feeding floors. Animal management within barns is "all in-all out" where feeder pigs are brought in at 50 lbs and finished to 250 lbs in 16 week cycles.

Ammonia was measured directly from barn exhaust fans, as well as manure pit exhaust fans using gas detection colorimetic tubes. Hydrogen sulfide was measured directly from barn exhaust fans, manure pit exhaust fans, as well as property lines using a Jerome 631-X Hydrogen Sulfide Analyzer. Odor was measured by gathering a bag of air from barn exhaust fans for lab analysis by dynamic olfactometry. Odor was also measured on-site using a Nasal Ranger Field Olfactometer.