Characterisation and source apportionment of atmospheric organic and elemental carbon in an urban–rural fringe area of Taiyuan, China

Abstract

Environmental contextCarbonaceous aerosols are major components of atmospheric fine-particulate material. We studied the characteristics and sources of carbonaceous aerosols in the urban–rural fringe area of Taiyuan, China, and found that pollutant levels were generally higher than in similar areas of northern China, and that vehicle emissions were the dominant source. The study highlights the importance of source analysis to help control pollution from particulate matter in the ambient air. AbstractThe concentrations of organic carbon (OC) and elemental carbon (EC) in fine particulate matter (PM2.5) were measured in 2017 at an urban–rural fringe area of Taiyuan. The annual average concentrations of PM2.5, OC and EC were 143±56, 13±8 and 10±6μgm−3 respectively, which were higher than those in most northern suburban and rural areas in China. Long-range transport and local resuspended dust caused by strong winds during the spring contributed strongly to PM2.5 mass concentrations. The OC and EC concentrations exhibited strong seasonal variations, with higher values in winter and spring, while poor correlations between OC and EC indicated the complexity of aerosol particle sources in winter and spring. Absolute principal component analysis (APCA) using eight carbon fractions was applied to determine the source contributions of total carbon (TC) in PM2.5. During winter, 61% of TC was attributed to mixed sources from coal combustion, biomass combustion and secondary organic carbon (SOC) formation, 23% to vehicle emissions, and 10% to regional origins. During spring, 57% of TC was attributed to vehicle exhaust, 18% to regional transport and SOC formation, and 13% to biomass burning. Comparative studies of hazy and non-hazy periods revealed the significance of SOC formation during hazy days.