Investigating the time-dependent dose–response relationship of ammonia emissions reduction through the application of a urease inhibitor in pig fattening houses

Abstract

In agricultural production, over 95% of ammonia emissions are released into the air. This released ammonia then reacts with other air pollutants to form particulate matter, endangering human health and ecosystems. One approach to counter this effect, which is directly related to the presence of the enzyme urease, is the use of a urease inhibitor. This study is the first to systematically investigate the time-dependent dose–response relationship between a urease inhibitor (dose levels: 10 mg m −2 , 25 mg m −2 and 50 mg m −2 ) and ammonia emissions in mechanically ventilated pig fattening houses over four experimental periods in one year. The inhibitor was applied simultaneously in five identical compartments on a daily basis. A new approach was used to determine the reduction effect by combining the case–control in time and direct case–control approaches. A maximum reduction of 21% in ammonia emissions was achieved in these experiments. The inhibitor had an effect on the first day, which lasted up to four days after the application phase. The higher the dose level of the inhibitor, the longer the reduction effect. Compared to cattle, higher dose levels of urease inhibitor are required for pigs. Further investigations on emission location within the compartment, on appropriate inhibitor doses levels depending on compartment design, animal behaviour or housing system as well as on automatic application systems are essential for the target-oriented use of a urease inhibitor in pig houses. • Dose–response relationship between a urease inhibitor and ammonia emissions. • A maximum reduction of 21% in ammonia emissions was achieved in these experiments. • The higher the dose level of the inhibitor, the longer the reduction effect. • Reduction calculation combines case–control in time and direct case–control.