Comparison of measured and modeled ambient hydrogen sulfide concentrations near a 4000 head swine facility

Air dispersion models are currently being used to regulate agriculture facilities and/or assess their environmental impact. As such, it is critical that these models accurately reflect these impacts. Meteorological conditions, hydrogen sulfide emissions, and downwind hydrogen sulfide concentrations at a four barn, 4000-head, swine finishing facility in Northeast Iowa were measured for a three week period in October 2003. Meteorological conditions and hydrogen sulfide emissions from the barns were used as inputs into two air dispersion models, INPUFF-2 and AERMOD. Model results were compared to measured results at eighteen receptor locations. Results indicate the models did not accurately predict spatial and temporal ambient concentrations. However, a rank order comparison of data (not matched in space and time) shows the models may be useful in predicting maximum concentrations over a period of time.