Fig. 6: Observed and WRF-Chem simulated sulfate concentrations and contributions of different sulfate formation pathways.
a Spatial distributions of WRF-Chem simulated sulfate concentrations in Experiment I during the three haze episodes in December 2016. b Same as a but for Experiment II. c Same as a but for Experiment III. d Comparison of the observed and WRF-Chem simulated sulfate concentrations during the three haze episodes in December 2016 at six sites, the locations of which are indicated by black dots in a. Error bars represent standard deviation. e Composition of particulate sulfur and contributions of different sulfate formation pathways to sulfate production during the six haze episodes in January 2015 and December 2016, including Mn-catalyzed oxidation of SO2 on aerosol surfaces (Mn_AS), reaction of S(IV) with H2O2 in aerosol water(H2O2_AW), gas phase oxidation (Gas phase), and other sulfate formation pathways (Others, including in-cloud oxidation and reactions of S(IV) with O3, NO2, and O2 catalyzed by TMIs in aerosol water). The contributions of each sulfate formation route were spatially averaged over the region with sulfate concentration >20 μg/m3. Maps were created by the authors using NCAR Command Language software Version 6.6.271.
