Unit-level assessment of mitigation pathways for mercury emissions from the global coal power fleet

Atmospheric mercury pollution remains a serious threat for human health and ecosystems, as recognized by the Minamata Convention on Mercury adopted in 2013. Coal-fired power units are major emitters of various environmental pollutants globally, including mercury. Here, we show the historical co-benefits of air pollution control measures and coal power retirement, identify coal-fired power units with disproportionately high mercury emissions, which we define as super emitters, and propose country-specific mitigation strategies. We find that super emitters were primarily concentrated in emerging countries by 2020. Our unit-level analysis highlights that substantial, near-term and cost-effective reductions can be achieved by prioritizing the retirement of super emitters and upgrading pollution control equipment, especially in countries with large coal fleets. In the long term, mercury-specific control technologies will be needed for deeper reductions. Our findings provide insights into customized and stage-based mitigation strategies for phasing down key sources of mercury emissions from coal-fired power units. A unit-level analysis highlights that substantial near-term and cost-effective reductions of mercury emissions can be achieved by prioritizing the retirement of super emitters and upgrading pollution control equipment; while in the long term, mercury-specific control technologies will be needed for deeper reductions.