Results from Livestock Facility Emissions Monitoring Released

June 22nd, 2005

A six-state study that involved air quality monitoring near swine and poultry facilities will help in the search for ways to reduce emissions.

Results from five of the states involved in the study were released June 22 at a meeting of the Air and Waste Management Association in Minneapolis. A $2.2 million USDA Initiative for Future Agriculture and Food Systems grant financed the project.

In Iowa, a mobile emissions laboratory recorded gas and particulate levels from a private swine finishing facility. The four-building site housed 1,000 pigs in each structure and included deep pits under the buildings that could store one year's worth of manure.

Steve Hoff, professor of agricultural and biosystems engineering at Iowa State University, shared the Iowa results at the Minneapolis meeting. "This research is the first step in providing producers, consultants, regulators and the public with accurate information on emission levels," Hoff said. "The emission levels will provide a basis to compare technologies aimed at reducing odors, gases and particles emitted from animal facilities."

Emissions sampling began Oct. 1, 2002 and continued through March 2004. Ammonia, hydrogen sulfide, particulates and carbon dioxide emissions were monitored continuously. Odors emitted also were sampled, and continuous weather monitoring was done.

Hoff said emissions data collected in Iowa shows ammonia levels were higher than hydrogen sulfide levels. "One of the things that surprised us is the highest ammonia levels did not occur when the manure pits were being agitated in preparation for land application," he said. "That was the time when hydrogen sulfide levels were at the highest, but they still did not exceed the ammonia emission levels."

Hoff said there are at least three different sets of air quality regulations under the Environmental Protection Agency (EPA) that could have an impact on livestock facility emissions. One is the Clean Air Act. "But the results are showing our swine production operations are nowhere close to violating the Clean Air Act," Hoff said.

Two other EPA programs are of greater concern - the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and the Emergency Planning and Community Right-To-Know Act (EPCRA). CERCLA established guidelines and procedures to respond to releases of hazardous substances, pollutants or contaminants. EPCRA is designed to help local communities protect public health, safety and the environment from chemical hazards.

Both CERCLA and EPCRA have lower proposed thresholds for ammonia and hydrogen sulfide emissions than the Clean Air Act. Hoff said the Iowa study showed ammonia levels would have exceeded the maximum allowed by CERCLA/EPCRA a few times in the spring of 2004. The hydrogen sulfide maximum never was exceeded.

Emissions from six types of animal confinement facilities were collected as part of this study. A poultry layer facility in Indiana and a broiler facility in North Carolina were included, as were three types of swine facilities in Minnesota, Illinois and Texas.

The Texas project was led by Jacek Koziel, who was with the Texas Agricultural Experiment Station during the monitoring phase. Koziel now is an assistant professor in Iowa State's agricultural and biosystems engineering department. He presented the Texas data at the June 22 meeting.

Koziel said the Texas research involved collecting emissions from two 1,000-head swine finishing barns. As was the case in Iowa, ammonia levels were the highest of any of the gases collected. But the average emission of 37 grams per animal unit (1 AU = 1,100 pounds) per day and the maximum of 78 grams were both lower than the Iowa numbers of 56 grams for the average and 131 grams for the maximum.

Hoff said the difference is that the Iowa study involved a finishing building and manure storage. The Texas project, plus the swine projects in Illinois and Minnesota, involved emissions from production buildings only.

"I think we have good emissions numbers now for swine finishing facilities with deep pits," Hoff said. "But the emissions that can be expected from outdoor manure storage units in addition to production barns still is unclear."

Data from the Illinois, Minnesota and Indiana projects also were presented at the June 22 meeting. A final report will be available this fall.

The EPA is in the process of working with industry groups to develop a new, two-year monitoring project that will gather emissions data from several more swine farms and manure storage facilities, plus more poultry houses and four free-stall dairy facilities.

A similar project is underway with Iowa State as the lead institution in a three-state effort that includes the University of Minnesota and the University of Nebraska. Hoff said the difference between the six-state project just completed and this newer one is that emissions are being collected and recorded simultaneously from swine facilities, plus locations downwind from those facilities. Monitoring for this two-year project began last summer and continues through this year.

The idea behind all this monitoring is to gather baseline information that can be used to evaluate differences in emissions due to geographical region, season of the year, time of day, building design, growth cycle of the animals and building management. Also, the EPA plans to establish new regulatory levels for emissions, once additional monitoring is complete.


Steve Hoff, Agricultural and Biosystems Engineering, (515) 294-6180,
Jacek Koziel, Agricultural and Biosystems Engineering, (515) 294-4206,
Susan Thompson, Communications Service, (515) 294-0705,