Seasonal Variation and Operational Impacts on Ammonia Emission Factors from Hanwoo Manure Composting

This study aimed to derive a more accurate and representative ammonia emission factor specifically for Hanwoo manure composting. We monitored real-time emissions using a large-scale flux chamber 2400 m³), which we modified from an actual composting shed at a Hanwoo ranch in Chuncheon. Measurements were conducted across summer, autumn, and winter using a laser-based ammonia analyzer. The results indicated that ammonia emissions followed a seasonal order of Summer (61.7633 μg s⁻¹ t⁻¹) > Autumn (38.8512 μg s⁻¹ t⁻¹) > Winter (8.3189 μg s⁻¹ t⁻¹). The final calculated emission factor was 0.8368 kgNH₃ yr⁻¹ animal⁻¹ as an all season average. While seasonal differences were statistically significant, hourly variations were less distinct compared to emission spikes induced by periodic mechanical agitation during the composting process. Our emission factor is significantly lower than national inventories, which is attributed to the inclusion of disturbances and the huge scale of the experimental chamber. These results offer a scientific foundation for updating the national inventory and provide a framework for future research on greenhouse gas emissions from diverse livestock sectors.