Fig. 2.

WRF-Chem simulated concentrations of biogenic SOA in the presence and absence of Manaus emissions. a Biogenic SOA when all emissions are on b Biogenic SOA when biogenic volatile organic compound (VOC) emissions are on but Manaus (anthropogenic) emissions are turned off c Biogenic SOA enhancement (%) calculated from the two simulations with Manaus emissions turned on/off i.e. (a–b)/b × 100. WRF-Chem predictions are at ~500 m altitude, averaged during the afternoon (16–20 UTC = 12–16 local time) of 13 March 2014