Estimating Ammonia Emissions and Nitrogen Mass Balance in the Po-Basin: Models, Tools, and Policy Implications

Within the LIFE PREPAIR project, the BAT-Tool Plus (released in February 2022) was developed to estimate ammonia (NH 3 ) and greenhouse gas emissions from intensive livestock farming in the Po-basin, a hotspot for agricultural air pollution. The tool applies a nitrogen mass balance approach, considering housing, storage, treatment, and land application phases, integrating EU Best Available Techniques (BAT) standards. The BAT-Tool includes high-resolution and tailored methodologies, allowing single farms and regional-scale simulations. In this study, the BAT-Tool was applied to the Po-basin using 2023 data from the National Livestock Database and regional statistics on manure management. The results show that around one-third of nitrogen excreted by livestock is lost as NH 3 , confirming livestock as the dominant source of emissions compared to fertilizers. In this paper, ammonia emissions and nitrogen load to fields were estimated, analyzing potential reductions achievable with wider adoption of BAT. The BAT-Tool provides standardized, transparent estimates, supporting regulatory compliance, emission inventories, and policy planning. Its scalability from farms to district scale makes it a reference model for improving nitrogen management and reducing PM 2.5 precursors in northern Italy and potentially across the EU.