ISU researchers are investigating swine emissions that may pose a health risk, even if they cannot be smelt.

ISU assistant professor and researcher Wendy Powers is leading a team to study ammonia emissions stemming from nitrogen in swine manure. She said there is no clear evidence ammonia from animal waste is a health problem, but that ammonia particulates may aggravate respiratory ailments.

“Our objective will be to modify rations to see if we can improve air quality,” said team member Jeff Lorimer. “Protein that you feed the animals is a nitrogen compound. Our main objective will be to reduce nitrogen in feed to see if that in turn will reduce some of the nitrogen that is in manure.”

Lorimer said some nitrogen is ultimately lost to the air as ammonia. Powers said cutting down ammonia levels may not result in an odor difference, but could reduce potential health risks.

Lorimer will study manure management as part of the project. “I’m kind of the manure guy here on campus,” he said.

During the study, 150-pound pigs will be individually crated in environmental chambers. The chambers will be constructed to catch feces and urine, and will also measure ammonia levels with air mass flow meters hooked to a computer system. Lorimer said the chambers will be expensive to build, but can later be used for other studies.

Brian Kerr, research leader at the National Swine Research and Information Center, is studying the use of amino acids in swine diets.

Kerr said the animo acids help pigs metabolize more efficiently, reducing overall manure production.

The first phase of the study is financed in part by the National Pork Board. Powers said it will be finished by May, and results may be published by June. Kerr said the study could impact farms, regardless of size, for both environmental and economic reasons.

The EPA and the state of Iowa are currently reconsidering Clean Air Act standards and may require lower ammonia levels in animal manures.