June 26, 2003

Urbana - More than 160 odorous compounds have been identified in dairy, beef, swine and poultry manure, according to Ted Funk, University of Illinois Extension specialist in environmental engineering.

Included on this list of offenders are gases such as ammonia and hydrogen sulfide, which can affect human health if they're at high levels. Because of the risk, Funk said some states have established air quality standards that limit emissions of hydrogen sulfide and ammonia from livestock and poultry operations. However, he added that most states agree there is not yet a sound scientific basis for determining fair and effective standards.

Other gases, such as ammonia, methane and carbon dioxide, can have implications for global warming and acid rain as well, Funk said. Methane, for example, can be produced by bacteria in liquid manure storages. It is estimated that one-third of the methane produced each year comes from agriculture--primarily generated by animals and manure storages or lagoons.

To keep these offenders in check, experts offer a variety of tips on how to control dust, odors and gases in key areas.

Livestock Buildings

Dust in livestock buildings originates from feed, bedding material, manure and the animals themselves. The amount of dust depends on animal activity, temperature, relative humidity, ventilation rate, stocking density and feeding methods.

Because dust often carries gases and odors, dust reduction in and around a building can also reduce odors. Some effective methods to control dust include: • Spraying a small amount of vegetable oil inside confinement buildings (one gallon per day in a 1,000-head swine finisher) • Windbreak walls, biomass filters and biofilters • Frequent cleaning of outdoor feedlots • Sprinkling water on open earthen lots in arid and semi-arid areas (typically done in late afternoons and evenings when animals are more active)

Manure Treatment/Storage Facility

Lagoons have a large surface, which increases gas emission and results in wide gas/odor plumes. Manure storage basins contain more concentrated manure than lagoons (for the same size operation) and produce less overall odor than lagoons. Storages have a narrower odor plume because of their small surface area. Covers can be very effective for outdoor storages.

While underfloor deep pits are better for outdoor air quality than outdoor storages, they result in poorer air quality within the building and can occasionally emit high levels of toxic hydrogen sulfide and other gases during agitation.

Land Application Areas

Over half of all odor complaints related to animal production occur when manure is applied on the land. Manure is typically applied to an area up to 700 times the surface area of the original storage, creating a large but short-term, downwind odor plume.

To significantly reduce odors, directly inject manure or till it into the soil within an hour after application.

Manure Transport Systems

Dust from truck and tractor traffic is often cited as a nuisance caused by animal operations. Sprinkling the roadbed of heavily-traveled gravel or unpaved roads with calcium chloride can reduce dust substantially.

Funk believes producers must also consider the perception of neighbors in their efforts to minimize the production of gases and dust at their facilities.

"The public has an increasing intolerance of odors," said Funk. "Maintaining general cleanliness and upkeep are an important part of being a good neighbor. Producers can't afford to ignore what others think of them or their operations."

For a more detailed description of procedures to measure and minimize a facility's impact on air quality, Midwest Plan Service has developed the publication Outdoor Air Quality (96 pages). Written for producers, this book includes an air quality model to help estimate the downwind odor impacts for a producer's operation.

Outdoor Air Quality is available for $17 plus shipping and handling fees from MWPS, Iowa State University, Ames, Iowa 50011-3080. To order, call 515-294-4337 or check their website at http://www.mwpshq.org.

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