A Study on the Characteristics of PM2.5 Components in Northeast Asia Using Observation Data and Air Quality Model

Northeast Asia is one of the regions with very high PM_2.5 concentrations, and in 2018 China mainland(41.2μg/m³) and Korea(24.0μg/m³) ranked 12 and 27 respectively in the PM_2.5 concentration ranking(2018 world air quality report). For effective PM_2.5 mass concentration reduction, research on the components of PM_2.5 is necessary. In this study, PM_2.5 concentration and components data were obtained during springtime 2015~2017 in Dalian, Changdao, Baengnyeong, Seoul, Oki and Rishiri site. Model simulations were performed by using the CMAQ version 4.7.1.

PM_2.5 mass concentrations during the monitoring period in 2016 are almost twice as high as those during the monitoring period in 2015. Especially, a considerable increase in the concentration of NO₃^- was found at the Dalian site and an increase in the concentration of SO₄^2- at the Changdao site. SO₄^2- (48-54%), NO₃^- (16-21%), and NH₄⁺ (25%) were the major chemical components in PM_2.5 at Baengnyeong site. Although Oki and Rishiri monitoring sites are located on small islands, Oki is on the same latitude as China and Korea; thus, the influence of anthropogenic emissions transported from China and Korea would be stronger in Oki than in Rishiri, which is in the northern part of Japan. The fractional ratio of the eight water-soluble ion components to total PM_2.5 mass increased gradually from China to Korea and Japan, and it was 35~41% at two sites in China, 31~51% in Korea, and 78~89% in Japan. Based on this analysis, we can assume that other chemical components (OC, EC, SOA, metals, etc.) excluded from in this analysis could decrease from China to Korea and Japan. In the model results, the proportion of each component in PM_2.5 appeared similarly, but the mass concentration showed a difference.