Rethinking of black-carbon associated organic particles: insights into aged biomass burning organic aerosol
Publication information:
J. Wang, J. Ye, D. Liu, Y. Wu, J. Zhao, W. Xu, C. Xie, F. Shen, J. Zhang, P.E. Ohno, Y. Qin, X. Zhao, S.T. Martin, and A.K.Y. Lee. 2020. “Rethinking of Black-Carbon Associated Organic Particles: Insights into Aged Biomass Burning Organic Aerosol”. Environmental Science & Technology
Abstract
Black carbon (BC) particles in Beijing summer haze play an important role in
regional radiation balance and related environmental processes. Understanding the
factors that lead to variability in the impacts of BC remains limited. Here, we present
observations by a soot-particle aerosol mass spectrometer of BC-containing submicron
particulate matter (BC-PM1) in the summer of 2017 in Beijing, China. These
observations were compared to concurrently measured total non-refractory submicron
particulate matter (NR-PM1) by a high-resolution aerosol mass spectrometer (HRAMS). Distinct variations were observed between NR-PM1 and BC-PM1 related to
organic aerosol (OA) composition with hydrocarbon-like OA in BC-PM1 up to twofold higher than that in NR-PM1 in fresh vehicle emissions, suggesting that a part of
HOA in BC-PM1 may be undetectable by HR-AMS. Cooking-related OA was only
identified in NR-PM1, whereas aged biomass burning OA (A-BBOA) was a unique
factor only identified in BC-PM1. The A-BBOA was linked to those heavily coated BC,
which may lead to enhancement of light absorption ability of BC by a factor of two via
the “lensing effect”. More-oxidized oxygenated OA identified in BC-containing
particles was found to be slightly different from that observed by HR-AMS, mainly due
to the influence of A-BBOA. Overall, these findings highlight that BC in urban Beijing
in June is partly of agricultural fire origin and, an unique biomass burning-related OA
associated with BC may be ubiquitous in aged BC-PM1, and this OA may play a role in
regional energy balance that has not previously been fully considered.
regional radiation balance and related environmental processes. Understanding the
factors that lead to variability in the impacts of BC remains limited. Here, we present
observations by a soot-particle aerosol mass spectrometer of BC-containing submicron
particulate matter (BC-PM1) in the summer of 2017 in Beijing, China. These
observations were compared to concurrently measured total non-refractory submicron
particulate matter (NR-PM1) by a high-resolution aerosol mass spectrometer (HRAMS). Distinct variations were observed between NR-PM1 and BC-PM1 related to
organic aerosol (OA) composition with hydrocarbon-like OA in BC-PM1 up to twofold higher than that in NR-PM1 in fresh vehicle emissions, suggesting that a part of
HOA in BC-PM1 may be undetectable by HR-AMS. Cooking-related OA was only
identified in NR-PM1, whereas aged biomass burning OA (A-BBOA) was a unique
factor only identified in BC-PM1. The A-BBOA was linked to those heavily coated BC,
which may lead to enhancement of light absorption ability of BC by a factor of two via
the “lensing effect”. More-oxidized oxygenated OA identified in BC-containing
particles was found to be slightly different from that observed by HR-AMS, mainly due
to the influence of A-BBOA. Overall, these findings highlight that BC in urban Beijing
in June is partly of agricultural fire origin and, an unique biomass burning-related OA
associated with BC may be ubiquitous in aged BC-PM1, and this OA may play a role in
regional energy balance that has not previously been fully considered.