Urease inhibitors: opportunities for meeting EU national obligations to reduce ammonia emission ceilings by 2030 in EU countries

Anthropogenic NH3 emissions, primarily from agriculture, have led to significant damage to human health and ecosystems. In the European Union (EU), the National Emission Ceilings (NEC) Directive 2016/2284/EU sets ambitious reduction targets by more than 30% for some countries by 2030 compared to 2005 levels. As urease inhibitors (UIs) can reduce the NH3 emission from urea by up to 70%, Germany has enforced their addition to granular urea by the national Fertilizer Ordinance since 2020. Therefore, this study investigates the implementation of UIs for urea fertilizers via national policy regulations to evaluate their contribution to achieving the 2030 targets in the EU countries. The results indicate that the contribution of UIs for countries with high reduction targets can reach 20%-60% of the required NEC reduction. The assessment of costs and benefits of UI implementation demonstrates that the ratio of benefits to costs can reach 70. Therefore, we recommend that adding UIs to urea fertilizers is one of the best strategies for mitigation of NH3 emissions not only in the EU but also in other regions such as China.