Evaluating gas and particulate matter emissions and downwind concentration impacts using the EPI air filter wall system

The EPI Air Filter Wall system is the combination of a windbreak wall (Air Filter Wall) installed exterior to the tunnel exhaust fans and an electrostatic precipitation system (EPS) to ionize the air and promote dust attraction to surfaces within the windbreak wall area. Data were collected at two production-scale finishing facilities with air filter walls over two summer periods to evaluate emission and downwind air quality impacts for the air filter wall, with and without the EPS system. Site A was a tri-barn with air filter walls exterior to the tunnel exhaust fans for two rooms managed similarly. Ammonia, hydrogen sulfide, methane and particulate gas data were collected at exhaust fans and around the Air Filter Wall systems, with and without the EPS. The EPS reduced ammonia (8%), carbon dioxide (7%) and methane (10%) concentrations of the air exhausted through the top opening area of the air filter wall relative to no EPS. There were no significant effects on hydrogen sulfide or particulate matter (PM10 or PM2.5) concentrations. Site B was a 1,200 head barn with an Air Filter Wall installed exterior to the tunnel exhaust fans on the north side of the barn. The EPS system was turned on and off weekly while air quality measurements were collected within the wall area, 61 m and 152 m to the north of the barn. The hourly mean ammonia concentration within the Air Filter Wall area at Site B varied between 0 and 36 ppm. There was only one instance when a concentration greater than 1 ppm registered at the sampling points 61 m and 152 m to the north of the barn. The average hourly mean hydrogen sulfide concentration within the Air Filter Wall area in 2020 was 300 ppb and the concentrations 61 m and 152 m from the barn were generally less than 10% of the concentration within the Air Filter Wall. There was no significant effect of the EPS system on hydrogen sulfide concentrations at any of the monitoring locations or on periodic particulate matter (PM10 or PM2.5) concentrations near the Air Filter Wall nor 61 m to the north of the barn. The visual impact of an air filter wall cannot be overlooked and short distance impacts are recognized. Air Filter Wall systems provide an option if and when producers are looking for partial emission reduction technologies for both new and existing facilities.