Oxidative Potential and Respiratory Deposition Rates of Size-resolved Particulate Matter

초록

This study investigated the size-resolved oxidative potential (OP) of particulate matter (PM) using a MOUDI sampler and evaluated its potential health impact by evaluating particle deposition in the human respiratory tract. Chuncheon, a medium-sized residential city in South Korea, was the measurement site for this study conducted in March 2023. The average of PM18 concentration during the study period was 39.7 mu g m(-3), showing a typical bimodal distribution with peaks in the 0.32 similar to 0.56 mu m and 3.2 similar to 5.6 mu m. Although PM mass was higher in the coarse mode, both OP measured by the ascorbic acid (OPAA) and dithiothreitol (OPDTT) assays peaked in the 0.32 similar to 0.56 mu m range, suggesting that fine particles may exert greater oxidative stress and pose elevated health risks. During Asian dust events, OPDTT increased in the coarse mode, indicating the influence of mineral-associated trace elements. Respiratory tract deposition modeling revealed that OPAA and OPDTT from fine particles were primarily deposited in the alveolar region. During non-dust periods, OPDTT showed relatively higher contributions from quasiultrafine and accumulation modes, while during Asian dust events, coarse-mode OPDTT was mainly deposited in the head airway region. These findings highlight the importance of particle size and composition in determining regional respiratory health risks. Further research is needed to identify the specific components driving size-dependent OP.

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