Oxidative potential of atmospheric aerosols: Research progress on pollution characteristics and mechanism

Aerosol oxidative potential (OP), as a key indicator characterizing its ability to generate reactive oxygen species (ROS), is directly related to the health effects of particulate matter. After a systematic review of global studies, it was found that the sensitivity of major OP measurement assays to chemical components varies significantly, and the regional pollution characteristics show a sharp contrast, which is mainly driven by biomass combustion, industrial emissions, and secondary transformation, etc. The mechanism of OP generation is complex, involving transition metal catalysis, redox of organics, such as Humus-like substances (HULIS), the synergistic effect of metal-organic complexation, and endotoxin (LPS) stimulation of inflammatory response. Notably, environmental persistent free radicals (EPFRs) form the basis for the long-term existence of aerosol OP. Three critical challenges need to be addressed in future work: to establish standardized determination of OP to solve the problem of methodological variability, to elucidate key formation and transformation mechanisms for source-oriented control, and to clarify the dose-response relationship of key toxic components. This review provides fundamental insights for subsequent research, and serves as a scientific basis for aerosol health risk assessment and environmental management.