Iowa State Involved in Nationwide Study of Air Quality

June 14th, 2007

AMES, Iowa - Researchers at Iowa State University are participating in the first-ever, nationwide study to measure gases and compounds emitted from livestock facilities, including poultry, dairy and swine operations.

The 2.5-year, $14.6 million study will measure levels of hydrogen sulfide, particulate matter, ammonia, nitrous oxide, volatile organic compounds and non-methane hydrocarbons released from livestock facilities. Air quality measurements will begin at most locations around the country soon and by fall will be underway at 14 monitoring sites in nine states.

The Iowa State portion of the project involves monitoring a swine operation. Jacek Koziel, associate professor of agricultural and biosystems engineering, leads the Iowa effort. "We have one of four sites with swine, with the others in North Carolina, Indiana and Oklahoma," he said. "Our gestation and farrowing site in central Iowa consists of three mechanically-ventilated barns with deep pit manure storage."

Besides Koziel, the Iowa State team includes Steve Hoff and Jay Harmon, both professors of agricultural and biosystems engineering. Work on establishing the on-site laboratory began in early May.

The overall study, which is being led by Purdue University, is designed to help establish science-based guidelines on livestock air emissions. Currently there is a lack of good data on these gases, which are regulated by the U.S. Environmental Protection Agency (EPA).

Two continuous years of emission data at concentrated animal feeding operations (CAFOs) and manure storage locations will be collected.

"This study will give the EPA the data it needs, plus allow researchers to develop strategies for reducing emissions when necessary," said Hoff.

Koziel said the study will help address concerns about odor emissions at CAFOs, although indirectly. "The EPA does not regulate odor. Instead the study will measure levels of particulate matter and gases that are thought to contribute to odor," he said.

As a follow-up to the current project, the monitoring equipment at the research sites also may be used to test strategies for reducing emissions. For example, researchers at Iowa State have found that less odor is emitted when exhaust air from livestock facilities passes through biofilters.

The results of the study also should help with educational efforts. "What we learn will help us prioritize and develop extension programs to show swine producers how to assess the air quality associated with their production and develop strategies to avoid and mitigate potential problems," said Harmon.

Besides Iowa State and Purdue, others participating in the study are University of California-Davis; Cornell University; University of Minnesota; North Carolina State University; Texas Agricultural Experiment Station; and Washington State University-Pullman.

The National Air Emission Monitoring Study is funded by the Agricultural Air Research Council, a non-profit organization funded by livestock industry groups. The study is being guided by the EPA Office of Air Quality Planning and Standards.


Jacek Koziel, Agricultural and Biosystems Engineering, (515) 294-4206,
Steve Hoff, Agricultural and Biosystems Engineering, (515) 294-6180,
Jay Harmon, Agricultural and Biosystems Engineering, (515) 294-0554,
Susan Thompson, Agriculture and Life Sciences Communication Service, (515) 294-0705,
Photos available from Susan Thompson. A video report is here: