Isotope characteristics of carbonaceous aerosols in urban atmosphere of China

Stable carbon isotopes were characterized for PM_2.5 organic carbon (OC) and elemental carbon (EC) at fourteen selected cities in China. The isotopic composition of OC varied averagely between 26.9 and -23.08% and EC varied between -26.63% and 23.27%. Strong relationship of stable carbon isotopic composition (δ¹³C) in OC and EC (R² = 0.70, p < 0.0001) was found for winter samples and poor relationship (R₂ = 0.1, p = 0.072) was found for summer samples in 14 cities. The winter to summer differences of δ¹³C_OC and δ¹³C_EC were large in seven north cities but there were relative small in seven south cities. Compared with the isotopic signature of major emission sources, the isotopic distributions in 14 cities implied the major sources of carbonaceous aerosol were from the combustion of fossil fuels including coal, gasoline, and diesel. The urban air in 7 cities in north China was influenced by coal combustion during winter. This is an abstract of a paper presented at the 103rd Air and Waste Management Association Annual Conference and Exhibition (Calgary, Alberta, Canada 6/22-25/2010).