By LINDA McGURK
Indiana Correspondent

WEST LAFAYETTE, Ind. — An extensive air-quality study, funded by livestock groups and led by researchers at Purdue University, could give the U.S. Environmental Protection Agency (EPA) a better understanding of emissions from large farms, and help farmers mitigate the cost of future regulations.
“Now we know much more about the magnitude of the problem. In some cases it’s not nearly as big as we thought and in some cases it’s a little bigger than we thought,” said Al Heber, a professor of agricultural and biological engineering at Purdue, who led the study.

The researchers measured for emissions of ammonia, hydrogen sulfide, volatile organic compounds and three sizes of particulate matter. Two add-on studies also measured for greenhouse gas emissions from the dairy industry and odor from dairy and swine operations.

“This was voluntary, pro-active, environmental research that the industry wanted,” said Heber. “They realized that regulations were on the horizon and that if they don’t have the data, the EPA will get it elsewhere.”

Because the EPA has lacked data on emissions from livestock farms, these have generally been exempt by default from the federal Clean Air Act, the law which defines EPA’s responsibilities for protecting and improving the nation’s air quality and the stratospheric ozone layer. But that approach has been challenged in court over the past 10 years, as livestock operations have grown bigger and neighbors and others have voiced concerns over odor and air quality.

“EPA recognized that it didn’t have enough scientific data to determine whether these farms were in violation of the Clean Air Act or not,” Heber said. “And the producer groups and the entire livestock industry were all interested in having process-based models to accurately estimate emissions from their operations.”
A 2005 consent agreement between the EPA and the livestock industry set the stage for the new study, which involved researchers at eight universities. For two years, emissions were measured from 38 barns on 14 farms in North Carolina, Iowa, Indiana, Oklahoma, California, New York, Washington and Wisconsin.

Five dairy sites, five pork production sites, three egg-layer sites and one broiler ranch were tested, as well as outdoor swine and dairy manure lagoons at nine farms, and a dairy corral in Texas. A 6,000-page data report from the two-year study was submitted to the EPA last year, and now the researchers involved are aiming to analyze the figures and extract information that could help livestock producers reduce emissions of air pollutants from their operations.
One observation researchers made was that manure collection systems could make a big difference in emission levels; for example, when comparing chicken operations that use manure belt houses, where manure is removed every day or two, with high-rises, where manure is typically removed once a year. “A lot less ammonia was emitted from the houses where manure is removed every day, and we know what that difference is,” Heber said.

Similar differences were noted in the dairy facilities’ manure handling systems. “One producer changed from a flushing to a scraping system and we saw a dramatic change in hydrogen sulfide emissions,” Heber said.

For chickens, emissions of particular matter increased every time new animals were brought in and then for about six weeks, until they settled into their cages. Aside from the manure collection systems, factors such as animal density, animal species, temperature, barn flow and the weather affected the level of emissions. For example, the researchers found that swine barns emit greater amounts of hydrogen sulfide than dairy free-stall barns.

When analyzing the data, which were collected using mobile laboratories and more than 2,300 sensors placed at participating farms, Heber said the research team expects to learn about “the effect of animal behavior on emissions, because we (have monitored) both their activity and their emissions in real time. We will learn about the effect of manure characteristics like pH and moisture content, and environmental parameters like temperature and wind on emission rates.”

The $14-million study was funded by the National Pork Board, National Chicken Council, National Milk Producers Federation and American Egg Board.
Though the EPA and state regulatory agencies will be the primary users of the data, Heber said this can also go a long way in helping the livestock industry prepare for and mitigate the cost of complying with future regulations.
“We’ve already analyzed the pork data and submitted it to the National Pork Board. Next month we’re doing eggs and after that, dairy,” he said.