The present study offers the first evaluation of organic and elemental carbon (OC and EC) of submicron (PM1) fraction in Changchun (Northeast China) during a year-long sampling period (October 24, 2016 to October 23, 2017). More than 288 PM1 (particulate matter with an aerodynamic diameter of less than 1 μm) samples were collected. The PM1 concentrations ranged from 3.78 to 451.08 μg·m-3, with an average of 57.73 μg·m-3, which was 1.65 times higher than the Chinese National Standard II. Following the concept of the well-known IMPROVE algorithm, OC and EC values were obtained. The OC values ranged from 1.18 to 82.54 μg∙m-3, and the EC values were from 0.30 to 14.19 μg∙m-3. Total carbon (TC = EC + OC) constituted 9.11-40.35% of the total PM1 mass, and OC dominated over EC. The average OC/EC ratio was 4.78, which implied a low percentage for vehicles and a high contribution of coal and biomass consumption to PM1. Among OC, the annual primary organic carbon (POC) value was 7.69 μg∙m-3, accounting for 63% of the OC, while secondary organic carbon (SOC) contributed 37% with 4.12 μg∙m-3. Among EC, CHAR (EC1) dominated over SOOT (EC2 + EC3), and the CHAR/SOOR ratio ranged from 2.91 to 28.55. The results of the OC and EC values as well as the OC/EC and CHAR/SOOT ratios suggest that possible sources of PM1 include vehicles, coal burning, cooking, and biomass burning.
Keywords: Elemental carbon; Northeast China; Organic carbon; PM1.