A review of atmospheric black carbon research progress in China

Black carbon (BC) is an atmospheric pollutant that adversely affects air quality, global climate, and human health. As an important BC source region, China has achieved substantial emission reductions over the past decade through stringent clean air policies, offering a unique opportunity to study changes of BC sources and properties under rapid emission changes. Concurrently, BC research in China has progressed rapidly, shifting from studying emission sources toward atmospheric processes and health impacts. This review focuses on five key topics in BC research, including ambient concentrations, emission sources, atmospheric aging, mixing state, and health effects. Ground observation networks and gridded datasets have shown a significant decrease in BC concentrations due to clean air policies, particularly in Northern and Eastern China. Emission inventories and source apportionment studies consistently identified fossil fuel combustion as the dominant BC source in China. Laboratory, field, and modeling studies have advanced understanding of BC aging and mixing state. The health evidence from China has linked BC exposure to respiratory, cardiovascular, and neurological diseases. The rapid expansion and heterogeneity of datasets underscore the urgent need for measurement standardization and cross-regional dataset comparison. In addition, this review calls for stronger integration of measurement and modeling to better study BC sources, aging, and mixing states, and highlights the need for assessing source-specific health impacts and understanding how atmospheric aging modifies BC toxicity.