Stable isotopic compositions of elemental carbon in PM1.1 in north suburb of Nanjing Region, China

• PM1.1 and EC pollutions were serious in north suburb of Nanjing region.
• The carbon sources of PM1.1 were traced and quantified with δ13C values during different seasons.
• δ13C values from potential sources for PM1.1 in Nanjing were systemically determined.

Stable isotopic compositions (δ13C) of elemental carbon (EC) in PM1.1 in north suburb of Nanjing region were determined in order to quantitatively evaluate the carbon sources of atmospheric fine particles during different seasons. Besides, δ13C values from potential sources such as coal combustion, vehicle exhaust, biomass burning, and dust were synchronously measured. The results showed that the average δ13C values of EC in PM1.1 in winter and summer were − 23.89 ± 1.6‰ and − 24.76 ± 0.9‰, respectively. Comparing with δ13C values from potential sources, we concluded that the main sources of EC in PM1.1 were from the emission of coal combustion and vehicle exhaust. The higher δ13C values in winter than those in summer were chiefly attributed to the more coal consumption. Combining with the concentrations of SO42 − and K+ in PM1.1, the high δ13C values of EC on 24 December and 27 December 2013 were ascribed to extra input of corn straw burning in addition to coal combustion and vehicle exhaust.