@article {270,
	title = {Pan-Arctic patterns in black carbon sources and fluvial discharges deduced from radiocarbon and PAH source apportionment markers in estuarine surface sediments},
	journal = {Global Biogeochemical Cycles},
	volume = {22},
	year = {2008},
	note = {id: 820; 307ZP Times Cited:3 Cited References Count:89Y},
	abstract = {A pan-arctic geospatial picture of black carbon (BC) characteristics was obtained from the seven largest arctic rivers by combining with molecular combustion markers (polycyclic aromatic hydrocarbons) and radiocarbon (C-14) analysis. The results suggested that the contribution from modern biomass burning to BC ranged from low in the Yukon (8\%) and Lena (5\%) Rivers to high in the Yenisey River (88\%). The Mackenzie River contributed almost half of the total arctic fluvial BC export of 202 kton a(-1) (kton = 10(9) g), with the five Russian-Arctic rivers contributing 10-36 kton a(-1) each. The C-14-based source estimate of fluvially exported BC to the Arctic Ocean, weighted by the riverine BC fluxes, amount to about 20\% from vegetation/biofuel burning and 80\% from C-14-extinct sources such as fossil fuel combustion and relict BC in uplifted source rocks. Combining these pan-arctic data with available estimates of BC export from other rivers gave a revised estimate of global riverine BC export flux of 26 x 10(3) kton a(-1). This is twice higher than a single previous estimate and confirms that river export of BC is a more important pathway of BC to the oceans than direct atmospheric deposition.},
	issn = {0886-6236},
	doi = {10.1029/2007gb002994},
	author = {Elmquist, M. and Semiletov, I. and Guo, L. D. and Gustafsson, O.}
}
@article {515,
	title = {Quantification and radiocarbon source apportionment of black carbon in atmospheric aerosols using the CTO-375 method},
	journal = {Atmospheric Environment},
	volume = {41},
	year = {2007},
	note = {id: 818; 243XB Times Cited:8 Cited References Count:58Y},
	pages = {7895-7906},
	abstract = {To make progress towards linking the atmosphere and biogeosphere parts of the black carbon (BC) cycle, a chemothermal oxidation method (CTO-375), commonly applied for isolating BC from complex geomatrices such as soils, sediments and aquatic particles, was applied to investigate the BC also in atmospheric particles. Concentrations and C-14-based source apportionment of CTO-375 based BC was established for a reference aerosol (NIST RM-8785) and for wintertime aerosols collected in Stockholm and in a Swedish background area. The results were compared with thermal-optical (OC/EC) measurements. For NIST RM-8785, a good agreement was found between the BCCTO-375 concentration and the reported elemental carbon (EC) concentration measured by the "Speciation Trends Network - National Institute of Occupational Safety and Health" method (ECNIOSH) with BCCTO-375 of 0.054+/-0.002gg(-1) and ECNIOSH of 0.067+/-0.008gg(-1). In contrast, there was an average factor of ca. 20 difference between BC(CTO-37)5 and ECNIOSH for the ambient Scandinavian wintertime aerosols, presumably reflecting a combination of BCCTO-375 isolating only the recalcitrant soot-BC portion of the BC continuum and the ECNIOSH metric inadvertently including some intrinsically non-pyrogenic organic matter. Isolation of BCCTO-375 with subsequent off-line radiocarbon analysis yielded fraction modern values (fM) for total organic carbon (TOC) of 0.93 (aerosols from a Swedish background area), and 0.58 (aerosols collected in Stockholm); whereas the fM for BCCTO-375 isolates were 1.08 (aerosols from a Swedish background area), and 0.87 (aerosols collected in Stockholm). This radiocarbon-based source apportionment suggests that contribution from biomass combustion to cold-season atmospheric BCCTO-375 in Stockholm was 70\% and in the background area 88\%. (C) 2007 Elsevier Ltd. All rights reserved.},
	issn = {1352-2310},
	doi = {10.1016/j.atmosenv.2007.06.006},
	author = {Zencak, Z. and Elmquist, M. and Gustafsson, O.}
}
