Stable carbon isotope of black carbon from typical emission sources in China

Abstract

Smoke particles from the three typical BC emission sources(biomass burning, household coal combustion, and vehicular exhaust) were collected and analyzed for stable carbon isotopes(δ13C) of black carbon(BC), total carbon(TC), as well as the original fuels. The results show that corn stalk(a typical C4 plant, -13.62‰) has the highest δ13CBC value, and the average values for C3 plants, bituminous coals, and vehicle exhaust are -26.49‰±1.17‰, -23.46‰±0.37‰, and -25.17‰±0.40‰, respectively. δ13CBC values from the three sources are similar to the corresponding fuels, and the ranges of these values are different from each other. Carbon fractionation occurs during the process of BC formation. δ13CBC for C4 plant(corn stalk)is lower than that of the fuel by 1.62‰, while the values for C3 plants and coals are higher than that of the fuels by 0.63‰ and 0.52‰, respectively. CTO- 375 method, which is used to extract BC from TC, affects the stable carbon isotope of smokes from biomass burning to some extent(the difference between δ13CBC and δ13CTC is nearly 0.50‰), but has little effect on fossil fuel smokes. This δ13C database for typical emission sources provides scientific information on BC source apportionment.