Purdue University researchers have delivered data to the Environmental Protection Agency on a two-year National Air Emissions Monitoring Study that gives a look at air quality on and around livestock farms.
Al Heber, a professor of agricultural and biological engineering and leader of the study, said he will now move to the next phase of his work: studying and publishing the dynamics and causes of the emissions and "mining" the extensive data for more information. At the same time, EPA is using the data to develop formulas that could be used by animal feeding operations or agencies to estimate their emissions.
"What we collected is baseline data," Heber said. "The quantity of emissions depend on how waste is collected, treated and stored; the number and type of animals; and the weather."
Heber and his team collected data from more than 2,300 sensors at a total of 38 barns on 14 farms in North Carolina, Iowa, Indiana, Oklahoma, California, New York, Washington and Wisconsin. For barns, there were five dairy sites, five pork production sites, three egg-layer sites and one broiler ranch. Outdoor swine and dairy manure lagoons were monitored at nine farms. A dairy corral in Texas also was tested.
The team measured for emissions of ammonia, hydrogen sulfide, three sizes of particulate matter and volatile organic compounds. Emission rates were calculated every minute.
"The dataset is very extensive," Heber said. "If we were to analyze 1 million data points per day, it would take us seven years to analyze - and that's just for the barns."
Heber said that estimates for these compounds at given types of farms will most likely be calculated from barn temperatures, animal density in the barns and barn airflow rate. Farm type is a major factor. For example, greater amounts of hydrogen sulfide are emitted from swine barns than from dairy freestall barns. And the type of manure collection systems, such as flushing versus scraping manure from barns, influences the numbers.
The National Pork Board, National Chicken Council, National Milk Producers Federation and American Egg Board funded the research through the nonprofit Agricultural Air Research Council. The EPA Office of Air Quality Planning and Standards oversaw the work and is currently developing emissions-estimating models from the data.
Purdue researchers collaborated with others at Cornell University, Iowa State University, North Carolina State University, Texas A&M University, the University of California-Davis, the University of Minnesota and Washington State University.