Analysis of the National Air Pollutant Emissions Inventory (CAPSS 2017) Data and Assessment of Emissions based on Air Quality Modeling in the Republic of Korea

Abstract

According to the 2017 National Air Pollutant Emissions Inventory (NEI), air pollutant emissions in the Republic of Korea comprised 817,420 metric tons (hereafter tons) of CO, 1,189,800 tons of NO_x, 315,530 tons of SO_x, 592,582 tons of TSP, 218,476 tons of PM₁₀, 91,731 tons of PM_2.5, 15,555 tons of black carbon (BC), 1,047,585 tons of VOCs, and 308,298 tons of NH₃. Emissions of the 13 first-level emission source categories, which constitute the NEI, were estimated and, based on their characteristics, the emission source categories were grouped into five sectors (energy, industry, road, non-road, and everyday activities and others). In addition, the contributions of primary PM_2.5 and its four precursors (NO_x, SO_x, VOCs, and NH₃) to the 2017 NEI were assessed in this study. The emission contributions of NO_x to the NEI were 36.5% for the road sector, which was the highest of those of all the air pollutants for this sector; NO_x emissions for this sector were 4.2% lower than those in the previous year. The emission contributions of SO_x and PM_2.5 to the NEI were higher than those of the other air pollutants for the industry sector; SO_x and PM_2.5 emissions for this sector decreased by 9.8% and 19.7%, respectively, compared with those in the previous year. The emission contributions of VOCs and NH₃ to the NEI were 65.3% and 83.9% for the everyday activities and others sector, respectively, higher than those of the other air pollutants for this sector; VOCs and NH₃ emissions for this sector increased by 0.8% and 2.9%, respectively, compared with those in the previous year. A three-dimensional (3D) chemical transport modeling system was used to validate the emission estimates. These data suggest that simulated SO_x emissions were overestimated in areas with dense large-scale industrial complexes, such as Jeollanam-do, Gyeongsangbuk-do, and Ulsan, and that simulated NO_x emissions were overestimated in Seoul, Incheon, and Jeollanam-do.