1. This study accurately quantified the unique δ¹⁵N signature of ammonia emissions from livestock and poultry in China. 2. Accurate regional source apportionment and targeted emission reduction strategies have been achieved. 3. The isotopic characteristics of ammonia emissions from livestock farms are significantly different from those of other sources. 4. The δ¹⁵N value is not directly correlated with ammonia concentration, but its variation is related to changes in emission levels.