“…The concentrations of diacids and oxoacids during the LCD increased by factors of 1.1 and 2.1, respectively, while α-dicarbonyls during the LCD were almost the same as before the LCD. The concentrations of diacids and TDOCs reported in this study were significantly lower than those in Xi'an (Cheng et al, 2013), Chengdu (Li et al, 2015), Tianjin (Devineni et al, 2023;Zhao et al, 2023), Liaocheng (Meng et al, 2020), 14 Chinese cities, and other Asian megacities such as Padori, Daejeon (Zhao et al, 2023), Ulaanbaatar (Jung et al, 2010), Chennai (Pavuluri et al, 2010), and Tokyo (Kawamura and Yasui, 2005), but they were similar to those in Beijing (Zhao et al, 2018) and Guangzhou (Ho et al, 2011) during the wintertime (Table S4).…”