Volatile organic compounds (VOCs) were determined by GC5000, an automatic on-line Gas Chromatography-Flame Ionization Detector. Elemental carbon (EC) and organic carbon (OC) were determined by the thermal/optical method using DRI-2001A during the periods of June 15th-July 15th 2015 and December 16th 2015-January 15th 2016. The concentration of secondary organic aerosol(SOA) was estimated by fractional aerosol coefficients (FAC) and EC tracer method. The source apportionment relied on the positive matrix factorization model (PMF). There were several conclusions:First, aromatic hydrocarbon was the main substance causing the SOA pollution in the Nanjing Industrial district, the contributions of aromatic hydrocarbon to SOA during summer and winter were 80.39% and 94.63%, respectively. The main contributers were benzene, toluene, ethylbenzene, m,p-xylene and o-xylene (BTEX). In the summer, SOA concentration ranged from 5.84-20.88 μg·m-3 with an average of 12.15 μg·m-3 and in the winter ranged from 2.17-17.73 μg·m-3 in which the average concentration was 6.91 μg·m-3. Secondly, SOA concentration decreased when wind and precipitation increased. By using the PMF model, a total of 7sources of SOA were determined in summer and 6 were determined in winter. There were 3 main sources in summer, including painting, petroleum processing and petrochemical industry, and the contributions to SOA were 0.65 μg·m-3, 0.21 μg·m-3, 0.18 μg·m-3, respectively. In winter, the most important SOA pollution was from painting, in which the contribution was 0.94 μg·m-3.
Keywords: EC tracer method; concentration of secondary organic aerosol; fractional aerosol coefficients(FAC); positive matrix factorization model and source apportionment; volatile organic compounds(VOCs).