New Air Quality Research Gets Underway at ISU

September 29th, 2002

AMES, Iowa - New research at Iowa State University may help answer questions about the relationship between swine production and air quality.

Two projects, both funded by the Iowa Pork Producers Association, are led by Wendy Powers, an assistant professor of animal science and an extension specialist. Her extension activities involve providing technical support and information to policymakers, producers and the public on environmentally sound agricultural practices.

Powers' research involves measuring and quantifying the various components of air quality, and in livestock production management techniques that might improve air quality.

Setting limits on ammonia, hydrogen sulfide and odor emissions from livestock facilities is under discussion in the state. Powers hopes her research will provide important information for policymakers examining these issues.

One project that includes Hongwei Xin and Jeff Lorimor, researchers in the agricultural and biosystems engineering department, will study both dietary and waste management strategies that might reduce ammonia levels in swine production facilities.

The ISU researchers will test ways to reduce ammonia levels by changing the makeup of the animals' diets. Some pigs will have their feed supplemented with one or more of three amino acids - lysine, methionine and threonine. Others will receive commercial dietary additives. These supplements and additives will be investigated on the theory they might stop the formation of ammonia or alter the compounds that lead to creation of ammonia.

Three strategies for reducing ammonia from swine waste also will be tested. One will measure ammonia levels when urine and feces are kept separate versus when the two are mixed. Another will involve adding an acid to the waste in an attempt to prevent ammonia from forming.

The third strategy will involve the use of chemicals that neutralize urease, an enzyme that causes the formation of ammonia. Powers says while this strategy already has shown promise, researchers know repeated applications will be needed so frequency and concentration of the urease inhibitors will be evaluated.

A second research project is gathering new information on emissions from Iowa swine facilities. It involves air sampling at and near seven swine production facilities in Iowa. Five swine finishing sites and two sow sites, each with a minimum of three buildings, will be monitored. Beginning last May, air samples were collected twice each week for 10 weeks from four locations at each site - the pit fan, and at locations 50, 100 and 200 feet downwind.

The samples were analyzed in Powers' lab in the National Swine Research and Information Center on the ISU campus. Each sample was analyzed for volatile organic carbons, which are compounds that contribute to odor as well as ozone formation and the formation of particulates. Hydrogen sulfide and odor levels also were recorded.

Powers hopes to gather air samples from the same seven sites next summer. She says the data will contribute to a computer model under development at Iowa State that will help producers make decisions on where to locate new livestock facilities.


Wendy Powers, Animal Science, (515) 294-1635

Susan Thompson, Agriculture Communications, (515) 294-0705

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