Modeling global atmospheric antimony (Sb) concentrations and depositions over the past two decades

As a priority contaminant regulated by environmental agencies, antimony (Sb) poses significant threats to both human health and marine ecosystems. However, the global long-term trends of particle-bound Sb concentrations and deposition fluxes remain poorly understood. To address this knowledge gap, we developed a 20-year global atmospheric Sb emission inventory (2000-2019) and, for the first time, simulated particle-bound Sb concentrations and deposition fluxes during this period. Our results revealed pronounced spatial variations in ambient Sb concentrations with the highest and lowest ones in China (1.49 ± 0.65 ng/m³) and Sub-Saharan Africa (SS: 0.007 ± 0.003 ng/m³), respectively. Regarding long-term trends, Sb concentrations in China increased steadily from 2000 to 2011 but declined sharply after 2013, likely due to the implementation of clean air policies. In contrast, India experienced a continuous rise in Sb levels since 2000, with no significant reduction in recent years. North America (NA) exhibited a persistent decline from 2000 to 2019, attributable to stable economic conditions and widespread adoption of advanced air pollution control technologies. Marine Sb deposition trends mirrored continental anthropogenic emission. For instance, deposition fluxes in the East China Sea (ECS) and North Atlantic Ocean (NAO) followed trends observed in China and Western Europe, respectively. Notably, total Sb depositions in remote oceans such as the Arctic Ocean (AO: +28%) and Southern Ocean (SO: +162%) increased markedly, underscoring the enduring influence of anthropogenic emissions on Sb deposition in even the most remote marine environments.