Fig. 1: Domains of this study.

a Modeling domain and b GOCI domain. Circles in the two domains represent the locations of ground-observation stations inside China and South Korea. Color codes of the circles indicate averaged PM2.5 during the KORUS-AQ campaign (between 1 May and 10 June, 2016). Regions A, B, and C are the Yellow Sea, North Korea, and the East Sea (or the Sea of Japan), respectively, where no surface PM2.5 information is available. Further, the three black squares in panel b mark the locations of the three cities in South Korea where further analyses were conducted.