Assessing Ammonia (NH₃) Emissions, Precursor Gas (SO₂, NO_x) Concentrations, and Source Contributions to Atmospheric PM_2.5 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, NO_x, NH₃) and PM_2.5 at a modern manure composting facility in Paju, South Korea. Over 35 days, average internal concentrations of NH₃, SO₂, and NO_x 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 PM_2.5 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 PM_2.5 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 PM_2.5, 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.