Quantification and radiocarbon source apportionment of black carbon in atmospheric aerosols using the CTO-375 method

Zencak, Zdenek; Elmquist, Marie; Gustafsson, Örjan

doi:10.1016/j.atmosenv.2007.06.006

Cited by 104 publications

(117 citation statements)

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“…The CTO-375 method has been widely used for quantification of soot-BC in sediments and soils (Gustafsson et al, 1997(Gustafsson et al, , 2001Gélinas et al, 2001;Elmquist et al, 2004Elmquist et al, , 2006 and aerosols (Zencak et al, 2007;Gustafsson et al, 2009). It has advantages such as being operatively simple and reasonably accurate.…”

Section: Environmental Significancementioning

confidence: 99%

“…Several prior studies used the CTO-375 method to quantify δ 13 C values for soot-BC materials in sediment and aerosol samples (Gélinas et al, 2001;Dickens et al, 2004;Zencak et al, 2007). The δ 13 C signatures were used from tracing the source materials of the BC and hence the ecological environment.…”

Section: Environmental Significancementioning

confidence: 99%

“…Several laboratory procedures including light microscopy, scanning and transmission electron microscopy, thermooptical transmission, and chemical and/or thermal oxidation followed by quantification with FTIR, molecular tracer proxies, or elemental analyses were used in the literature for quantifying BC in environmental samples (Lim and Cachier, 1996;Gustafsson et al, 1997Gustafsson et al, , 2001Song et al, 2002;Brodowski et al, 2005;Hammes et al, 2007). Among these tested methods, the chemothermal oxidation (CTO) method has gained much attention as operatively simple and reasonably accurate measurements for soot-BC in soils and sediments (Gustafsson et al, 1997(Gustafsson et al, , 2001Gélinas et al, 2001;Elmquist et al, 2004Elmquist et al, , 2006 and later also soot-BC in aerosols (Zencak et al, 2007;Gustafsson et al, 2009). For instance, the large-scale distribution of combustion-derived and sorptive PAHs in marine sediments have repeatedly been shown to be much better explained by CTO375-based BC than by bulk OC or any other parameter (e.g., Gustafsson and Gschwend, 1998;Persson et al, 2002;Oen et al, 2006;Sanchez-Garcia et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…In prior studies (Dickens et al, 2004;Zencak et al, 2007;Andersson et al, 2011), the CTO-375 method was used for eliminating non-BC materials from environmental samples, and the residue carbonaceous materials were combusted at higher temperatures for quantifying both the contents and the δ 13 C and Δ 14 C isotope compositions of the BC. Using such a method, Dickens et al (2004) measured carbon isotope compositions for graphitic BC samples isolated from both marine and terrestrial sediments of pre-industrial ages using the above approach.…”

Section: Introductionmentioning

confidence: 99%

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Stability and carbon isotope changes of soot and char materials during thermal oxidation: Implication for quantification and source appointment

2012

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Section: Environmental Significancementioning

confidence: 99%

Section: Environmental Significancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Stability and carbon isotope changes of soot and char materials during thermal oxidation: Implication for quantification and source appointment

2012

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“…A future inter-comparison of these three and also other methods (e.g., Zencak et al, 2007;Heal et al, 2011) would shed more light on the issue how strongly the differences in the extraction protocols affect F 14 C (EC r ). Such an intercomparison has been done for organic and total carbon (Szidat et al, 2013), but only very limited data on EC were available at that time.…”

mentioning

confidence: 99%

Evaluation of a two-step thermal method for separating organic and elemental carbon for radiocarbon analysis

et al. 2014

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Abstract. We thoroughly characterized a system for thermal separation of organic carbon (OC) and elemental carbon (EC) for subsequent radiocarbon analysis. Different organic compounds as well as ambient aerosol filter samples were introduced into an oven system and combusted to CO 2 in pure O 2 . The main objective was to test which combustion times and temperatures are best suited to separate OC and EC. The final separation step for OC was combustion at 360 • C for 15 min. Combustion at this temperature proved enough to remove several organic test substances from the filter (including high molecular weight humic acid) but did not remove substantial amounts of EC. For isolation of EC, OC first needs to be completely removed from the filter. This was achieved by water extraction of the filter, followed by combustion of the water insoluble OC at 360 • C and combustion at an intermediate temperature step of 2 min at 450 • C. This last step removed the most refractory OC together with some EC. Finally, the remaining EC was combusted to CO 2 at 650 • C. The recovery of black carbon after the intermediate 450 • C step was approximately 80 %. Several tests provided strong evidence that OC was removed efficiently during the intermediate temperature step: (i) brown carbon, indicative of refractory OC, was removed; (ii) the fraction modern of EC did not decrease significantly if the temperature of the intermediate step was further increased. Based on tests with various organic compounds, we estimated that charred organic carbon could contribute 4-8 % to an elemental carbon sample that was isolated according to our method.

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Water-soluble organic carbon aerosols during a full New Delhi winter: Isotope-based source apportionment and optical properties

Кириллова

Andersson

Tiwari

et al. 2014

J. Geophys. Res. Atmos.

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219

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Water-soluble organic carbon (WSOC) is a major constituent (~20-80%) of the total organic carbon aerosol over the Indian subcontinent during the dry winter season. Due to its multiple primary and secondary formation pathways, the sources of WSOC are poorly characterized. In this study, we present radiocarbon constraints on the biomass versus fossil sources of WSOC in PM 2.5 for the 2010/2011 winter period for the megacity Delhi, situated in the northern part of the heavily polluted Indo-Gangetic Plain. The fossil fuel contribution to Delhi WSOC (21 ± 4%) is similar to that recently found at two South Asian background sites. In contrast, the stable carbon isotopic composition of Delhi WSOC is less enriched in 13 C relative to that at the two receptor sites. Although potentially influenced also by source variability, this indicates that near-source WSOC is less affected by atmospheric aging. In addition, the light absorptive properties of Delhi WSOC were studied. The mass absorption cross section at 365 nm (MAC 365 ) was 1.1-2.7 m 2 /g with an Absorption Ångström Exponent ranging between 3.1 and 9.3. Using a simplistic model the relative absorptive forcing of the WSOC compared to elemental carbon in 2010/2011 wintertime Delhi was estimated to range between 3 and 11%. Taken together, this near-source study shows that WSOC in urban Delhi comes mainly (79%) from biomass burning/biogenic sources. Furthermore, it is less influenced by photochemical aging compared to WSOC at South Asian regional receptor sites and contributes with a relatively small direct absorptive forcing effect.

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Quantification and radiocarbon source apportionment of black carbon in atmospheric aerosols using the CTO-375 method

Cited by 104 publications

References 52 publications

Stability and carbon isotope changes of soot and char materials during thermal oxidation: Implication for quantification and source appointment

Stability and carbon isotope changes of soot and char materials during thermal oxidation: Implication for quantification and source appointment

Evaluation of a two-step thermal method for separating organic and elemental carbon for radiocarbon analysis

Water-soluble organic carbon aerosols during a full New Delhi winter: Isotope-based source apportionment and optical properties

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