Uncovering the Global Burden and Future Trajectories of Nanomagnetite Particle Emissions from Biomass Power Plants

assays demonstrate that nanomagnetite particles (NMPs) constitute a disproportionately toxic subfraction of fine particles: despite contributing only 2.3% of particle mass, NMPs account for 59% of cytotoxicity. On this basis, we quantify NMP emissions from BPPs by integrating measured NMP concentrations with data-augmented machine-learning models and unit-level activities. The resulting global inventory shows strong spatial disparities, with national average concentrations ranging from 150 to over 2000 mg/kg and total global emissions reaching 230 (92-530) t in 2024. Asia contributes 45% of global emissions, followed by South America (26%) and Europe (20%), driven by differences in feedstock composition, installed capacity, and dust removal performance. Scenario projections further indicate that deployment of advanced dust removal technologies under a carbon-neutrality-oriented pathway could reduce global NMP emissions to 76 t by 2050. These results reveal a previously unrecognized source of nanoscale pollution and provide a quantitative framework for integrating NMPs into future bioenergy and air-quality strategies.