Analysis of national air pollutant emissions in 2020 and re-estimation results for emissions from past years (2016–2019)

The National Air Emission Inventory and Research Center (NAIR) has refined emissions estimation methods to enhance the accuracy and reliability of national statistics on air pollutant emissions. The center estimated 2020 national emissions by applying 23 items identified to have been improved from the improvement research and re-estimated the national emissions from 2016 to 2019 to secure the coherence of national annual emissions. This study compares national emissions of the past years before and after the re-estimation and analyzes the major causes of changes in 2020 national emissions compared to those of 2019.

The re-estimation of national emissions from 2016 to 2019 revealed the following change rates for each substance: CO, − 5.5 to 5.8%; NOx, − 3.9 to 1.8%; SOx, − 14.7 to − 0.6%; PM_2.5, − 31.5 to − 27.0%; VOCs, − 1.3 to 1.1%; NH₃, − 15.4 to 14.3%; and BC, − 4.9% to 5.5%. National air pollutant emissions in 2020 were as follows: CO, 711,399 tons; NOx, 929,227 tons; SOx, 180,157 tons; PM_2.5, 58,558 tons; VOCs, 990,629 tons; and NH₃, 261,207 tons. It turned out that the year-on-year reduction rates of emissions were as follows: CO, − 5.5%; NOx, − 11.1%; SOx, − 23.9%; PM_2.5, − 4.9%; VOCs, − 2.0%; NH₃, − 2.9%; and BC, − 11.6%.

National statistics on air pollutant emissions serve as basic data for establishing, implementing, and evaluating national atmospheric environment policies to improve air quality. It is necessary to establish effective atmospheric environment policies based on highly accurate emission statistics to improve air quality. To this end, it is imperative to conduct ongoing research including studies on improving the national air pollutant emissions estimation method as well as on verifying emissions using air quality modeling and satellite observation data.