책임운영기관 농촌진흥청 국립축산과학원

Ammonia is an air pollutant that affects both ambient air quality and worker health, and has recently been identified as a precursor to the formation of fine particulate matter (PM2.5). Accordingly, the livestock sector is increasingly required to develop technologies to mitigate ammonia emissions. This study evaluated the effect of benzoic acidsupplemented diets on reducing ammonia emissions from pig barn and quantified the total free ammonia emissions (potential emissions) based on slurry composition, thereby establishing a causal relationship for ammonia mitigation. Ammonia concentrations were measured in real-time both inside the pig barn and at the exhaust outlets, and the annual ammonia emission factor was calculated by incorporating ventilation rates and number of pigs. And, slurry samples were collected weekly and analyzed for key chemical parameters such as pH, electrical conductivity, ammonium nitrogen concentration etc. The results showed that the annual ammonia emission factor was represented a 54.5% reduction upon feeding with benzoic acid-supplemented diets (0.5 kg/head-year) compared to control (1.1 kg/head-year). In addition, the both pH and ammonium nitrogen concentrations in the slurry were significantly lower in the treatment, with the ammonium nitrogen concentration decreasing by an average of 34.0%. Furthermore, the estimated total free ammonia emissions, calculated based on slurry pH and ammonium nitrogen concentration, showed a trend similar to the actual measured emissions at the exhaust fan. On an 8-week average basis, the total free ammonia emissions was reduced by 66.1%, and the actual emission by 58.8% in the treatment. These results demonstrate that the benzoic acid-supplemented diets fundamentally reduces the volatilization potential of ammonia by altering the chemical composition of the slurry. This study provides field-based evidence of the effectiveness of feed additive-based ammonia mitigation strategies and quantitatively estimates the potential ammonia emissions to elucidate the causal relationship underlying the mitigation effect.