An optimised organic carbon ∕ elemental carbon (OC ∕ EC) fraction separation method for radiocarbon source apportionment applied to low-loaded Arctic aerosol filters
-
Published:2023-02-14
Issue:3
Volume:16
Page:825-844
-
ISSN:1867-8548
-
Container-title:Atmospheric Measurement Techniques
-
language:en
-
Short-container-title:Atmos. Meas. Tech.
Author:
Rauber MartinORCID, Salazar Gary, Yttri Karl EspenORCID, Szidat SönkeORCID
Abstract
Abstract. Radiocarbon (14C) analysis of carbonaceous aerosols
is used for source apportionment, separating the carbon content into fossil
vs. non-fossil origin, and is particularly useful when applied to
subfractions of total carbon (TC), i.e. elemental carbon (EC), organic
carbon (OC), water-soluble OC (WSOC), and water-insoluble OC (WINSOC).
However, this requires an unbiased physical separation of these fractions,
which is difficult to achieve. Separation of EC from OC using
thermal–optical analysis (TOA) can cause EC loss during the OC removal step
and form artificial EC from pyrolysis of OC (i.e. so-called charring), both
distorting the 14C analysis of EC. Previous work has shown that water
extraction reduces charring. Here, we apply a new combination of a WSOC
extraction and 14C analysis method with an optimised OC/EC separation
that is coupled with a novel approach of thermal-desorption modelling for
compensation of EC losses. As water-soluble components promote the formation
of pyrolytic carbon, water extraction was used to minimise the charring
artefact of EC and the eluate subjected to chemical wet oxidation to
CO2 before direct 14C analysis in a gas-accepting accelerator mass
spectrometer (AMS). This approach was applied to 13 aerosol filter samples
collected at the Arctic Zeppelin Observatory (Svalbard) in 2017 and 2018,
covering all seasons, which bear challenges for a simplified 14C source
apportionment due to their low loading and the large portion of pyrolysable
species. Our approach provided a mean EC yield of 0.87±0.07 and
reduced the charring to 6.5 % of the recovered EC amounts. The mean
fraction modern (F14C) over all seasons was 0.85±0.17 for TC;
0.61±0.17 and 0.66±0.16 for EC before and after correction
with the thermal-desorption model, respectively; and 0.81±0.20 for
WSOC.
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference102 articles.
1. Abbatt, J. P. D., Leaitch, W. R., Aliabadi, A. A., Bertram, A. K., Blanchet, J.-P., Boivin-Rioux, A., Bozem, H., Burkart, J., Chang, R. Y. W., Charette, J., Chaubey, J. P., Christensen, R. J., Cirisan, A., Collins, D. B., Croft, B., Dionne, J., Evans, G. J., Fletcher, C. G., Galí, M., Ghahreman, R., Girard, E., Gong, W., Gosselin, M., Gourdal, M., Hanna, S. J., Hayashida, H., Herber, A. B., Hesaraki, S., Hoor, P., Huang, L., Hussherr, R., Irish, V. E., Keita, S. A., Kodros, J. K., Köllner, F., Kolonjari, F., Kunkel, D., Ladino, L. A., Law, K., Levasseur, M., Libois, Q., Liggio, J., Lizotte, M., Macdonald, K. M., Mahmood, R., Martin, R. V., Mason, R. H., Miller, L. A., Moravek, A., Mortenson, E., Mungall, E. L., Murphy, J. G., Namazi, M., Norman, A.-L., O'Neill, N. T., Pierce, J. R., Russell, L. M., Schneider, J., Schulz, H., Sharma, S., Si, M., Staebler, R. M., Steiner, N. S., Thomas, J. L., von Salzen, K., Wentzell, J. J. B., Willis, M. D., Wentworth, G. R., Xu, J.-W., and Yakobi-Hancock, J. D.: Overview paper: New insights into aerosol and climate in the Arctic, Atmos. Chem. Phys., 19, 2527–2560, https://doi.org/10.5194/acp-19-2527-2019, 2019. 2. Agrios, K., Salazar, G., Zhang, Y.-L., Uglietti, C., Battaglia, M.,
Luginbühl, M., Ciobanu, V. G., Vonwiller, M., and Szidat, S.: Online
coupling of pure O2 thermo-optical methods – 14C AMS for source
apportionment of carbonaceous aerosols, Instrum. Meth. B, 361, 288–293,
https://doi.org/10.1016/j.nimb.2015.06.008, 2015. 3. Andersson, A., Sheesley, R. J., Kruså, M., Johansson, C., and
Gustafsson, Ö.: 14C-Based source assessment of soot aerosols in
Stockholm and the Swedish EMEP-Aspvreten regional background site, Atmos.
Environ., 45, 215–222, https://doi.org/10.1016/j.atmosenv.2010.09.015, 2011. 4. Barrett, T. E., Robinson, E. M., Usenko, S., and Sheesley, R. J.: Source
Contributions to Wintertime Elemental and Organic Carbon in the Western
Arctic Based on Radiocarbon and Tracer Apportionment, Environ. Sci.
Technol., 49, 11631–11639, https://doi.org/10.1021/acs.est.5b03081, 2015. 5. Barrie, L. A.: Arctic air pollution: An overview of current knowledge,
Atmos. Environ., 20, 643–663, https://doi.org/10.1016/0004-6981(86)90180-0, 1986.
Cited by
1 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|