Global ammonia emission could be halved with cost-effective measures

Ammonia (NH ₃ ) emissions pose significant threats to ecosystems and human health globally, yet a comprehensive assessment of mitigation strategies' costs and benefits remains elusive. Here, we employ a multi-model framework to evaluate 32 mitigation measures across seven sectors in 185 countries. Our analysis reveals that implementing these measures, particularly in agriculture, could reduce global NH ₃ emissions by 49%. The estimated implementation cost of $279 billion is substantially outweighed by projected environmental, health, and resource benefits of $568 billion. China and India emerge as countries with the highest potential net societal benefits from NH ₃ mitigation. Future scenario analysis demonstrates a potential 55% decrease in NH ₃ emissions by 2050 under a sustainability pathway, contrasting with up to 19% increases under scenarios with low climate and nitrogen policy ambitions. These findings underscore the urgent need for international action and national policies to establish effective NH ₃ mitigation targets and pathways.