Regional Differences in PM2.5 Chemical Composition and Inhalation Risk Assessment: A Case Study of Seoul, Incheon, and Wonju

This study evaluates the chemical components of an aerodynamic diameter less than 2.5 μm (PM_2.5) and its health risks in Seoul, Incheon, and Wonju, South Korea. The results revealed significant regional variations, particularly under the reasonable maximum exposure scenario, with Seoul's average daily dose (6.4 × 10^-1 µg/kg/day) approximately 2 times higher than Incheon (5.8 × 10^-1 µg/kg/day) and Wonju (3.2 × 10^-1 µg/kg/day) under the central tendency exposure scenario. Furthermore, exposure to the chemical components comprising PM_2.5 can surpass risk thresholds when PM_2.5 concentrations exceed the national standard levels. These findings suggest the potential benefits of preventive measures, such as minimizing outdoor exposure, especially for individuals over 60 years of age, to help reduce health risks. However, further research is needed to confirm the effectiveness of these measures in different regions. The study also highlighted the variation in the health impacts of PM_2.5 concentrations and its chemical components across the different regions. The results suggest that relying solely on PM_2.5 concentrations for health risk assessments may underestimate the risks associated with carcinogenic components such as chromium (Cr, VI). However, under the reasonable maximum exposure (RME) scenario, the excess cancer risk (ECR) for Cr (VI) exceeds the acceptable threshold in all three regions, suggesting a high carcinogenic risk under the RME scenario. For example, the ECR for Cr(VI) in Seoul was calculated as 1.4 × 10^-4, Incheon as 2.0 × 10^-4, and Wonju as 1.2 × 10^-4. Therefore, we emphasize the importance of incorporating both the mass concentration of PM_2.5 and its chemical constituents when conducting health risk assessments to inform region-specific health policies to mitigate health risks, particularly for vulnerable populations.