Strengthen Mercury Control in Coal Use in the Perspective of Global Flows: From Input to Waste

Coal-derived mercury is the dominant anthropogenic source of mercury emissions. Current sector-specific control may lead to emission leakage via unaccounted cross-sector transfers, particularly during waste treatment. Here, we traced mercury flows across the entire coal-use industrial chain─from production and trade to utilization and waste disposal─offering a comprehensive view of emissions. In 2017, global coal use released 1362 tonnes of mercury, with 705 tonnes emitted into the atmosphere (including 221 tonnes re-emitted from waste disposal), 316 tonnes retained in stock, 275 tonnes stabilized, and the rest discharged into water or soil. Based on the mercury flow, our study identified country-specific key priorities for emission control. Southeast Asian and African nations urgently need advanced end-of-pipe control technologies to reduce emissions. The U.S. (grappling with solid waste stockpiling) and China (facing secondary waste emissions) must improve stabilization methods. Major coal importers like Japan should limit mercury content in imported coal, and countries with strong regulations, such as the EU, must align energy reforms with climate targets. Our study provides a novel, system-wide perspective on mercury pollution throughout the coal life cycle, supporting whole-process control in coal use and the implementation of the Minamata Convention.