Predicting Ambient Hydrogen Sulfide Concentrations Near Animal Feedlots

Larry Jacobson, Professor
David Schmidt, Assistant Extension Engineer
Verlyn Johnson, Information Technology Professional

Funding Source

Minnesota Agricultural Experiment Station Rapid Agricultural Response Fund

Objective

To develop a quick, easy, and economical tool for assessing an animal feedlot’s potential to exceed Minnesota’s ambient air quality standard for hydrogen sulfide (H2S).

Need or Impact

The need exists for a screening tool to be developed for assessing the potential of animal feedlots to meet the Minnesota state ambient air quality standard for hydrogen sulfide (30 ppb - not to be exceeded more than twice in 5 days or 50 ppb - not to be exceeded more than twice in one year, 30 minute averages at the property line). Current methods for assessing this potential require individual, site-specific computer modeling that is often cost prohibitive to many producers. With the current economic challenges associated with animal agriculture, a low cost, high quality assessment tool is important for the maintenance and growth of the state’s livestock industry.

Project Status

Three air dispersion models, INPUFF2, AERMOD, and CALPUFF, are being used to simulate downwind conditions from selected simulated or case farms. A ten-member advisory/stakeholder group met twice in 2005 to provide input on policy and technical issues for the project. Results have shown setbacks that are larger then what has been predicted site specifically, but those have used H2S emission rates lower than what is presently being found from monitoring studies.