Air Dispersion Modeling

A hog grower in Missouri was required to control emissions of hydrogen sulfide, ammonia and particulate matter 10 microns in diameter or smaller (PM10). Burns & McDonnell performed air dispersion modeling on various emission mitigation measures to predict potential concentrations of these three pollutants. The modeling showed that potential worst-case emissions of hydrogen sulfide, ammonia and particulate matter did not exceed their respective National Ambient Air Quality Standards (NAAQS) or the Missouri Ambient Air Quality Standard (MAAQS).

• Air dispersion modeling
• Control technology evaluation

The Missouri Department of Natural Resources (MDNR) determined the confidential hog grower was the main emission source of hydrogen sulfide, ammonia and PM10 that caused nearby ambient air monitors to register values in excess of their respective NAAQS or MAAQS.

Burns & McDonnell, in conjunction with an environmental controls vendor, the MDNR and an environmental attorney, modeled controlled emissions from a permeable lagoon cover, seasonal emission factors for hydrogen sulfide, nutrient reduction cells to minimize nitrogen transformation to ammonia and regularly watered haul roads.

The air dispersion model was set up using the standard ISCST3 modeling defaults. The total number of finishing barns modeled was over 150, the number of lagoons was 25 and more than 20 miles of haul roads. Each barn, lagoon and haul road segment was setup as a separate emission source. Meteorological data was for the years 1995-99 and approved by the MDNR.

• Air dispersion model using EPA approved ISCST3 model
• Predicted impacts of permeable lagoon cover
• Analysis of emissions from finishing barns, manure lagoons and haul roads