Characterization\nof Oxidative Potential and Ecotoxicity\nof the Organic Fraction of Particulate Matter in a Coastal City in\nChina: Implications for Human Respiratory Health

This study investigated the size distributions, oxidative\npotential\n(OP<sub>v</sub>), and acute ecotoxicity index (TI) of atmospheric\norganic aerosols during haze and nonhaze periods in a coastal city\nin China. Results indicated higher OP<sub>v</sub> and TI levels during\nhaze periods, with trimodal variations: the highest OP<sub>v</sub> peak in the 7.2–10 μm and the highest TI peak in the\n0–0.49 μm. For the first time, multilayer perception\nanalysis was applied to predict both OP<sub>v</sub> and ecotoxicity,\noffering enhanced accuracy by capturing synergistic and antagonistic\ninteractions among various chemical components. Lung deposition doses\nof size-resolved PM inducing OP<sub>v</sub> and TI within the human\nrespiratory system were estimated. Findings revealed that the largest\nparticles (7.2–10 μm) predominantly affected the head\nairways, whereas particles in the 1.5–3.0 μm significantly\nimpacted the pulmonary region. This behavior is attributed to quinones\nand high-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs),\nwhich have higher deposition efficiency in the head airways and elevated\nconcentrations in the pulmonary region, respectively. To mitigate\nhealth risks associated with these toxicants, efforts should target\ntheir size-dependent properties and lung deposition efficiency, considering\nvarious health end points. This study underscores the need for size-specific\nmitigation strategies to effectively address the differential impacts\nof PM on respiratory health.