Source Quantification of South Asian Black Carbon Aerosols with Isotopes and Modeling
| Published | 4 September 2020 |
|---|---|
| Journal | Environmental Science & Technology |
| Volume | 54 |
| Issue | 19 |
| Pages | 11771-11779 |
| Publisher | American Chemical Society (ACS) |
| DOI | 10.1021/acs.est.0c02193 |
Open access (hybrid)
Carbonaceous aerosols: black carbon and brown carbon
Abstract
Black carbon (BC) aerosols perturb climate and impoverish air quality/human health─affecting ∼1.5 billion people in South Asia. However, the lack of source-diagnostic observations of BC is hindering the evaluation of uncertain bottom-up emission inventories (EIs) and thereby also models/policies. Here, we present dual-isotope-based (Δ14C/δ13C) fingerprinting of wintertime BC at two receptor sites of the continental outflow. Our results show a remarkable similarity in contributions of biomass and fossil combustion, both from the site capturing the highly populated highly polluted Indo-Gangetic Plain footprint (IGP; Δ14C-fbiomass = 50 ± 3%) and the second site in the N. Indian Ocean representing a wider South Asian footprint (52 ± 6%). Yet, both sites reflect distinct δ13C-fingerprints, indicating a distinguishable contribution of C4-biomass burning from peninsular India (PI). Tailored-model-predicted season-averaged BC concentrations (700 ± 440 ng m–3) match observations (740 ± 250 ng m–3), however, unveiling a systematically increasing model-observation bias (+19% to −53%) through winter. Inclusion of BC from open burning alone does not reconcile predictions (fbiomass = 44 ± 8%) with observations. Direct source-segregated comparison reveals regional offsets in anthropogenic emission fluxes in EIs, overestimated fossil-BC in the IGP, and underestimated biomass-BC in PI, which contributes to the model-observation bias. This ground-truthing pinpoints uncertainties in BC emission sources, which benefit both climate/air-quality modeling and mitigation policies in South Asia.
Abstract © the authors, published under a CC BY licence.
Cite this
Sanjeev Dasari, August Andersson, Andreas Stohl, Nikolaos Evangeliou, Srinivas Bikkina, Henry Holmstrand, Krishnakant Budhavant, Abdus Salam, Örjan Gustafsson (2020). Source Quantification of South Asian Black Carbon Aerosols with Isotopes and Modeling. Environmental Science & Technology, 54(19), 11771-11779. https://doi.org/10.1021/acs.est.0c02193
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