“…Many recent regional and global modelling studies (Fu et al, 2008;Knote et al, 2014;Hu et al, 2017;Stadtler et al, 2018;Bates and Jacob, 2019;Liu et al, 2020;Qiu et al, 2020;Xu et al, 2020), as well as several studies constrained by in-situ field observations (Volkamer et al, 2007;Washenfelder et al, 2011;Li et al, 2016;Ling et al, 2020), have reported that CHOCHO contributes 0 to 25 % to SOA formation. This large variability resulted from the different conditions of the individual studies, focusing on different VOC precursors, biogenic (Li et al, 2016;Xu et al, 2020) vs anthropogenic (Volkamer et al, 2007;Liu et al, 2020;Qiu et al, 2020), and using different simulation tools, such as, 0-D box (Volkamer et al, 2007), Lagrangian (Washenfelder et al, 2011), and 3-D transport models (Fu et al, 2008;Knote et al, 2014;Chan Miller et al, 2016;Li et al, 2016;Chan Miller et al, 2017;Sareen et al, 2017;Hu et al, 2017;Liu et al, 2020;Qiu et al, 2020;Xu et al, 2020). These model studies were run with (Washenfelder et al, 2011) or without (Volkamer et al, 2007;Knote et al, 2014) steady-state assumption for CHOCHO, and employed different aerosol uptake treatments such as surface uptake only (Washenfelder et al, 2011;Li et al, 2016) or allowing simultaneous volume control processes (Knote et al, 2014;Ling et al, 2020).…”