Among the Organization for Economic Co-operation and Development (OECD) countries, South Korea has the highest population exposure to PM2.5. Although the country’s diverse PM2.5 reduction policies have improved the pollution levels, the PM2.5 concentrations still pose serious environmental and health risks. Herein, we monitored the physicochemical components, such as ion, metal, organic carbon/ elemental carbon (OC/EC), and particle number concentrations, across different regions in South Korea for January 1–December 31, 2021. The study area consisted of the city center, industrial complexes, and suburban areas. Before analyzing the emission characteristics of each site, we compared the Clean Air Policy Support System (CAPSS) data for the three areas, to analyze the main emission sources. The annual particle number concentrations for the three areas were 21.8–26.44 µg/m3; the maximum values were evident in March. All the three areas portrayed high ratios of NO3− with different components in all seasons. The particle number concentrations in the three sites were 1.3–1.5 × 107, and the peak points of the concentrations were different in every site: city center (40 nm), industrial complexes (60 nm), and suburban areas (80 nm). We also conducted potential source contribution function (PSCF) and conditional bivariate probability function (CBPF) analyses, to determine the inflow direction of the pollution sources, for high PM2.5 episodes. For the episodes that occurred in spring and winter, there were no differences in the PM2.5 concentrations between the three sites. This study can serve as a framework for developing air-quality management policies in South Korea.
