Anthropogenic atmospheric heavy metal emission inventories in China: Theoretical frameworks, methodological evolution, and future perspectives

Heavy metals (HMs) pollution is a global environmental and public health concern due to its persistence, bioaccumulation, and toxicity. Reliable atmospheric HM emission inventories (AHMEI) are essential for identifying source characteristics and supporting air pollution mitigation policies. This study summarizes the historical evolution and methodological advances in AHMEI quantification, including both top-down and bottom-up approaches. In China, coal combustion and non-ferrous metal smelting remained major HM sources around 2010. Peak emission intensities were concentrated in central-eastern and southern China, especially in economically developed provinces. Stringent regulations and improved control technologies have promoted integrated multi-pollutant strategies, leading to 17% to 84% decreases in Pb, Hg, Cd, As, and Cr emissions from 2015 to 2020. The total HM emissions from major industrial point sources showed declining trends during this period, whereas Hg emissions remained challenging, fluctuating between 300 and 500 t. Despite progress using dynamic emission factor models, Monte Carlo uncertainty analysis, and high-resolution spatial modeling, developing countries still face barriers to high-resolution AHMEI because of limited source data and model uncertainty. In addition, complex industrial structures and regional disparities hinder robust interpretation and sustained reduction. Future AHMEI should advance toward dynamic, multi-pollution, high-resolution frameworks integrating cross-media transfer and species transformation. Emission control policies should align with China’s Green Industrial Restructuring, the Beautiful China Initiative, and the Dual-Carbon Goals to support sustainable development.