Fig. 4: Radiocarbon-based source apportionment of dicarboxylic acids and related compounds.
From: Large contribution of fossil-derived components to aqueous secondary organic aerosols in China
a Relationships between biogenic/biomass burning (bio/bb) source-derived oxalic acid vs. levoglucosan. b Relationships between bio/bb source-derived oxalic acid vs. biogenic secondary organic aerosol (SOA) tracer (include isoprene SOA tracers and α/β−pinene SOA tracers; Supplementary Method 1). c Monthly variability of non-fossil contribution to oxalic acid, malonic acid, succinic acid, glyoxylic acid, and methylglyoxal. The error bars represent ±1 standard deviation for total propagated uncertainty (Supplementary Method 3). d Relative contribution of biogenic emission, biomass burning, and fossil-fuel emission to oxalic acid in coastal background and continental outflow.
