Analysis of air quality based on national monitoring networks in the Republic of Korea, 2023 - annual trends in air quality over two decades in South Korea-

In this study, to assess the long-term air quality status in South Korea, we analyzed the concentration and attainment rate of air quality standards for 8 pollutants such as SO₂, NO₂, CO, O₃, PM₁₀, PM₂.₅, Pb, and benzene. In 2023, the average concentrations were as follows: PM₁₀ 37 µg/m³, PM₂.₅ 19 µg/m³, SO₂ 0.0025 ppm, NO₂ 0.0135 ppm, CO 0.39 ppm, O₃ 0.0327 ppm, Pb 0.01979 µg/m³, and benzene 0.64 µg/m³. Due to ongoing strict emission control policies, PM₂.₅ and NO₂ levels have decreased by approximately 27% and 43%, respectively, compared to 2015. Other pollutants, including SO₂, CO, PM₁₀, Pb, and benzene, also showed significant reductions, ranging from 36% to 74%, over the analyzed period. However, O₃ levels have shown a 73% increase since 1998. Primary pollutants have generally decreased in concentration with higher attainment rate for air quality standards, whereas PM₂.₅, a secondary pollutant, still exhibits a low attainment rate of less than 20% in 2023 despite concentration reductions. Likewise, low attainment rate coupled with rising O₃ levels indicate a need to focus on secondary pollutants in future air quality management policies. This study provides long-term observational data on air pollutants in South Korea, which can aid in understanding air quality across East Asia and help to make a direction ongoing air quality improvement policy.