Investigation of Secondary Particulate Matter Formation in a Layer Barn

Abstract

Ammonia and acid gases react to form fine secondary inorganic aerosols (SIA). Due to the elevated ammonia and particulate matter (PM) levels in poultry houses, it is possible that SIA are partly responsible for the high fine PM concentrations. Hence, the objectives of this study were to develop a methodology to quantify the concentrations of secondary particulates and total PM in a small-scale layer facility to investigate the possibility of SIA formation arising from interactions between ammonia and the acid gases. The instrumentation used to estimate the SIA species was an annular denuder system (ADS) with a two-stage filter pack. The ADS was used to strip the ammonia and acid gases from the sample air stream before collecting particulates on a Teflon filter with a backup nylon filter. Filter extractions were analyzed with an ion chromatography system to determine concentrations of the ion species. In addition, two particle counters were used to measure the total PM2.5 and PM10 in the layer facility. Three air samples were taken from inside the layer house. SIA concentrations were found to be approximately 0.033, 0.011, 0.025 mg/m3 in the air samples, which were all significantly higher than background concentrations near the air intakes. Also, secondary PM contributed to roughly 50, 47, and 99% of the total PM2.5 in the house. These preliminary findings suggest that SIA are formed in poultry houses and, as such, it may be feasible to reduce PM levels by directly targeting ammonia and/or the acid gases.