Characteristics and Source Analysis of Carbonaceous Components of PM2.5 During Autumn in the Northern Suburb of Nanjing

: In this study, PM2.5 samples were collected from October to November of 2015 in the northern suburb of Nanjing. The mass concentrations of organic carbon (OC), elemental carbon (EC), and levoglucosan in the samples were analyzed by thermal optical transmittance (TOT) and ion chromatography. The average concentrations of OC and EC were respectively (11.3±4.9) μg·m-3 and (1.1±0.9) μg·m-3. The average total carbon (TC) was 22.9%, and the OC/EC was 7.4. The quality concentrations of PM2.5, OC, EC, and SOC all reflected daytime features, and the correlation between OC and EC was better during the day than at night (correlation coefficients of 0.86 for day and 0.7 for night). By analyzing the mass concentrations of PM2.5, levoglucosan, and SOC, as well as the data of backward trajectories and fire point data, it was determined that the northern suburb of Nanjing is affected by the long-distance transportation of biomass from Hebei and other places from October 13-16. The correlations between levoglucosan and OC, EC, or SOC were significant (correlation coefficients of 0.78, 0.79, and 0.65, respectively), and the contribution of biomass combustion during sampling to OC was 21.9%.