Dynamic Ammonia Emission Patterns and Recovery from Growing-Finishing Pig Houses
This study investigated the dynamic characteristics and recovery of ammonia emissions from a growing-finishing pig house in Yanshi District, Luoyang City, Henan Province, China. High-sensitivity electrochemical sensors and an ammonia absorption recovery device were employed for continuous monitoring and treatment of exhaust air. The results revealed periodic fluctuations in ammonia emission concentrations, strongly correlated with indoor temperature and humidity. Over the entire monitoring period, the average daily ammonia concentration in exhaust air was 9.852 mg·m−3, below the national emission limit of 25 mg·m−3. However, during high-temperature periods (>30 °C), localized concentrations reached 38.36 mg·m−3. Humidity, particularly from spray cooling, temporarily suppressed ammonia volatilization, but its effect was modulated by temperature. Total ammonia emitted during the study was 1380.4 kg, with an average per-pig emission rate of 0.034 kg·d−1. After treatment with the exhaust gas absorption device, the average daily ammonia concentration dropped to 0.437 mg·m−3, achieving a mean recovery efficiency of 93.5%. These findings demonstrate that controlling environmental factors and employing external air absorption devices can significantly reduce ammonia emissions, offering a viable pathway for mitigating nitrogen pollution from livestock operations and promoting resource recovery.