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

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 PM 10 , 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 NH 3 . 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 NH 3 ) 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 NH 3 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 NH 3 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.