Characteristics and source apportionment of PM2.5-bound saccharides and carboxylic acids in Central Shanghai, China

Abstract PM2.5-bound of a group of thirty-six polar organic compounds including seventeen saccharides and nineteen carboxylic acids and PM2.5 were analyzed for the abundance and potential sources at three sites in central Shanghai, China from September 2015 to August 2016. The annual average concentrations of the total saccharides in the PM2.5 was 184.9 ng/m3 with concentrations ranging from 15.3–873.4 ng/m3 for all samples. Principal component analysis coupled with multiple linear regression (PCA-MLR) revealed that 53% of saccharides in Shanghai were derived from biomass combustion emission, 25% from fungal spore emission and 22% from plant emission. The annual average concentration of total acids concentration was 122.5 ng/m3. Pollutants showed seasonal variations with significant higher concentrations of the dicarboxylic acid, anhydrosugar and sugar alcohol in winter and primary sugar such as fructose and sucrose in spring and summer. Lower ratios of adipic acid (C6)/azelaic acid (C9) and phthalic acid (Ph)/C9 indicated that aerosols in Shanghai are more influenced by biogenic sources. Three PCA factors explained 84% of the variance of the studied carboxylic acids data. The PCA results showed that secondary aerosols(both from anthropogenic and biogenic sources)and biomass burning emissions were the most important sources of carboxylic acids in Shanghai.