Isotope constraints of the strong influence of biomass burning to climate-forcing Black Carbon aerosols over Southeast Asia

Junwen Liu; August Andersson; Guangcai Zhong; Xiaofei Geng; Ping Ding; Sanyuan Zhu; Zhineng Cheng; Mohamad Pauzi Zakaria; Chui Wei Bong; Jun Li; Junyu Zheng; Gan Zhang; Örjan Gustafsson

doi:10.1016/j.scitotenv.2020.140359

Isotope constraints of the strong influence of biomass burning to climate-forcing Black Carbon aerosols over Southeast Asia

Sci Total Environ. 2020 Nov 20:744:140359. doi: 10.1016/j.scitotenv.2020.140359. Epub 2020 Jul 3.

Authors

Affiliations

¹ Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China; Department of Environmental Science, Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Jinan University, Guangzhou, China.
² Department of Environmental Science, Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden.
³ State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China.
⁴ State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China.
⁵ Institute of Ocean and Earth Sciences, University of Malaya, Kuala Lumpur, Malaysia.
⁶ Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Jinan University, Guangzhou, China.
⁷ State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China. Electronic address: zhanggan@gig.ac.cn.
⁸ Department of Environmental Science, Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden. Electronic address: orjan.gustafsson@aces.su.se.

PMID: 32688001
DOI: 10.1016/j.scitotenv.2020.140359

Abstract

Black Carbon (BC) deteriorates air quality and contributes to climate warming, yet its regionally- and seasonally-varying emission sources are poorly constrained. Here we employ natural abundance radiocarbon (¹⁴C) measurements of BC intercepted at a northern Malaysia regional receptor site, Bachok, to quantify the relative biomass vs. fossil source contributions of atmospheric BC, in a first year-round study for SE Asia (December 2015-December 2016). The annual average ¹⁴C signature suggests as large contributions from biomass burning as from fossil fuel combustion. This is similar to findings from analogous measurements at S Asian receptors sites (~50% biomass burning), while E Asia sites are dominated by fossil emission (~20% biomass burning). The ¹⁴C-based source fingerprinting of BC in the dry spring season in SE Asia signals an even more elevated biomass burning contribution (~70% or even higher), presumably from forest, shrub and agricultural fires. This is consistent with this period showing also elevated ratio of organic carbon to BC (up from ~5 to 30) and estimates of BC emissions from satellite fire data. Hence, the present study emphasizes the importance of mitigating dry season vegetation fires in SE Asia.

Keywords: Biomass burning; Black Carbon; Radiocarbon; SE Asia.