[Stable carbon isotopic composition in PM 2.1 in Nanjing Region]

Stable carbon isotopes (delta13C) in aerosol fine particles (PM2.1) collected in Nanjing Normal University representing urban area, and in Nanjing College of Chemical Technology standing for suburban industrial area, were analyzed using EA-IRMS. Besides, sources of carbonaceous contents were studied and the pollution characteristics of total carbon (TC) were evaluated. The annual average concentrations of TC in urban area and suburban industrial area were 15.94 microg.m-3 and 17.17 microg.m-3, respectively. The proportions for TC in PM2.1 were 17.18% and 16. 40% , indicating that carbonaceous pollution was more serious and the pollutants were more complex in suburban industrial area. The average delta13C for winter, spring, summer and autumn were -24. 42 per thousand +/- 1. 12 per thousand, -25. 19 per thousand +/- 1. 92% per thousand, - 25.79 per thousand +/- 0.45 per thousand and - 25.58 per thousand + 0. 65 per thousand, respectively in urban area and - 25.34 per thousand +/- 1. 18 per thousand, -25. 55 per thousand +/- 1. 50 per thousand, -25. 31 per thousand +/- 0. 55%o and -25. 38 per thousand +/- 0. 82 per thousand, respectively in suburban area. Correlation analysis and isotopic signatures of potential sources suggested that carbonaceous contents mainly came from gasoline vehicles exhaust in urban area, and might be attributed to the vehicle exhaust emissions and industrial emissions in suburban area. In addition, coal combustion,biomass burning and geological sources might have important contribution to aerosols in winter and spring. Back trajectory analysis implied that the long-range transport had considerable contribution to the carbonaceous aerosol in winter and spring. However, the major sources might be attributed to local emissions in the other two seasons.