Assessing Ammonia (NH₃) Emissions, Precursor Gas (SO2, NOx) Concentrations, and Source Contributions to Atmospheric PM2.5 from a Commercial Manure Composting Facility

Increased ammonia (NH3) emissions from intensive agriculture negatively affect environmental and ecosystem health, contributing to formation of particulate matter (PM) and the potent greenhouse gas, N2O. Better understanding NH3 emissions from the manure composting process and their behavior as a constituent of the atmospheric aerosol load is a crucial element in creating better farm management systems, improving public health outcomes, and mitigating the broader environmental and climatic impacts of agriculture. Retarded generation of PM with a major constituent source of NH3 is a primary mechanism for evaluating the effects of agricultural contribution to PM. This study aimed to quantify NH3 emissions, examine the influence of environmental factors, and investigate the relationship between precursor gases (SO2, NOx, NH3) and PM2.5 at a modern manure composting facility in Paju, South Korea. Over 35 days, average internal concentrations of NH3, SO2, and NOx were significantly higher than external levels. NH3 concentrations reached 3.64 ± 0.06 mg m−3 at 3 m height and 2.43 ± 0.16 mg m−3 at ground level, while the total NH3 flux from the facility was 24.47 ± 1.39 NH3-N kg d−1. Internal PM2.5 concentrations (36.9 ± 2.6 µg m−3) were about 50% higher than external levels (23.7 ± 2 µg m−3), with a moderate correlation (r = 0.341) suggesting some contribution of external PM2.5 to internal levels. Despite large quantities of internal emissions, the facility’s sealed design with a negative pressure ventilation system effectively minimized external emissions. These results suggest that while manure composting facilities are significant sources of NH3 and PM2.5, advanced systems like high-volume ventilation and scrubbing technologies can effectively reduce their impact on regional air pollution, contributing to better environmental management in agriculture.