Combined influences of sources and atmospheric bleaching on light absorption of water-soluble brown carbon aerosols

Wenzheng Fang, August Andersson, Meehye Lee, Mei Zheng, Ke Du, Sang Woo Kim, Henry Holmstrand, Örjan Gustafsson

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1 Citation (Scopus)


Light-absorbing Brown Carbon (BrC) aerosols partially offset the overall climate-cooling of aerosols. However, the evolution of BrC light-absorption during atmospheric transport is poorly constrained. Here, we utilize optical properties, ageing-diagnostic δ13C-BrC and transport time to deduce that the mass absorption cross-section (MACWS-BrC) is decreasing by ~50% during long-range oversea transport, resulting in a first-order bleaching rate of 0.24 day‒1 during the 3-day transit from continental East Asia to a south-east Yellow Sea receptor. A modern 14C signal points to a strong inverse correlation between BrC light-absorption and age of the source material. Combining this with results for South Asia reveals a striking agreement between these two major-emission regions of rapid photobleaching of BrC with a higher intrinsic absorptivity for BrC stemming from biomass burning. The consistency of bleaching parameters constrained independently for the outflows of both East and South Asia indicates that the weakening of BrC light absorption, thus primarily related to photochemical processes rather than sources, is likely a ubiquitous phenomenon.

Original languageEnglish
Article number104
Journalnpj Climate and Atmospheric Science
Issue number1
Publication statusPublished - 2023 Dec

Bibliographical note

Funding Information:
This work was supported by a combination of Swedish, Chinese, EU and South Korean funding sources. We acknowledge the Swedish Research Council (FORMAS grant no. 942-2015-1061 and VR Distinguished Professorship grant to Ö. G., no. 2017-01601). W.F. acknowledges the start-up funding from East China Normal University and EU financial support from Marie Curie individual fellow programme (H2020-MSCA-IF-GA-2014-659529). K.D. acknowledges the support from the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (XDB05060200) for aerosol sampling. S.-W.K. was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education (2017R1D1A1B06032548).

Publisher Copyright:
© 2023, The Author(s).

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Atmospheric Science


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