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Characteristics of BrC and BC emissions from controlled diffusion flame and diesel engine combustion

Malmborg, Vilhelm LU orcid ; Eriksson, Axel LU orcid ; Gren, Louise LU ; Török, Sandra LU ; Shamun, Sam LU ; Novakovic, Maja LU ; Zhang, Yilong ; Kook, Sanghoon ; Tunér, Martin LU and Bengtsson, Per Erik LU orcid , et al. (2021) In Aerosol Science and Technology 55(7). p.769-784
Abstract

Constraining the climate impact of particulate brown carbon (BrC) will require identification of formation mechanisms and isolation of its different components to allow for source apportionment. For fresh combustion aerosols, the light absorption characteristics and the Absorption Ångstrom Exponent (AAE) are principally controlled by the combustion conditions in which the particles formed and evolved. We investigated the influence of combustion temperatures on the BrC or black carbon (BC) emission characteristics for a miniCAST soot generator (propane fuel) and a modern heavy-duty diesel engine (petroleum diesel and two renewable diesel fuels). Changes in the AAE, mass spectral signatures, and thermal-optical characteristics were... (More)

Constraining the climate impact of particulate brown carbon (BrC) will require identification of formation mechanisms and isolation of its different components to allow for source apportionment. For fresh combustion aerosols, the light absorption characteristics and the Absorption Ångstrom Exponent (AAE) are principally controlled by the combustion conditions in which the particles formed and evolved. We investigated the influence of combustion temperatures on the BrC or black carbon (BC) emission characteristics for a miniCAST soot generator (propane fuel) and a modern heavy-duty diesel engine (petroleum diesel and two renewable diesel fuels). Changes in the AAE, mass spectral signatures, and thermal-optical characteristics were studied. We show that changing operating parameters to gradually reduce the combustion temperatures in these two fundamentally different combustion devices result in a regression from BC dominated to BrC dominated particle emissions. The regression toward BrC was associated with: (1) an increasing mass fraction of particulate non-refractory polycyclic aromatic hydrocarbons (PAHs), (2) an increasing fraction of refractory organic carbon, (3) more curved soot nanostructures and shorter fringe lengths, and (4) increased signal from (refractory) large carbon fragments in IR laser-vaporization aerosol mass spectra. Based on these results we argue that fresh BrC dominated combustion aerosols are attributed to primary emissions from low temperature combustion, highlighting the influence of refractory constituents and soot nanostructure. Higher temperatures favor the growth of conjugated polyaromatic structures in the soot, a progression hypothesized to control the evolution from BrC to BC character of the emitted aerosols.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Matti Maricq
in
Aerosol Science and Technology
volume
55
issue
7
pages
769 - 784
publisher
Taylor & Francis
external identifiers
  • scopus:85103590040
ISSN
0278-6826
DOI
10.1080/02786826.2021.1896674
project
Black carbon precursors in combustion emissions: Implications for health effects, short-lived climate forcing and emission mitigation
language
English
LU publication?
yes
id
8aa10280-b4d7-4f8c-8726-491516bec0f1
date added to LUP
2021-04-13 14:01:22
date last changed
2025-04-04 14:47:46
@article{8aa10280-b4d7-4f8c-8726-491516bec0f1,
  abstract     = {{<p>Constraining the climate impact of particulate brown carbon (BrC) will require identification of formation mechanisms and isolation of its different components to allow for source apportionment. For fresh combustion aerosols, the light absorption characteristics and the Absorption Ångstrom Exponent (AAE) are principally controlled by the combustion conditions in which the particles formed and evolved. We investigated the influence of combustion temperatures on the BrC or black carbon (BC) emission characteristics for a miniCAST soot generator (propane fuel) and a modern heavy-duty diesel engine (petroleum diesel and two renewable diesel fuels). Changes in the AAE, mass spectral signatures, and thermal-optical characteristics were studied. We show that changing operating parameters to gradually reduce the combustion temperatures in these two fundamentally different combustion devices result in a regression from BC dominated to BrC dominated particle emissions. The regression toward BrC was associated with: (1) an increasing mass fraction of particulate non-refractory polycyclic aromatic hydrocarbons (PAHs), (2) an increasing fraction of refractory organic carbon, (3) more curved soot nanostructures and shorter fringe lengths, and (4) increased signal from (refractory) large carbon fragments in IR laser-vaporization aerosol mass spectra. Based on these results we argue that fresh BrC dominated combustion aerosols are attributed to primary emissions from low temperature combustion, highlighting the influence of refractory constituents and soot nanostructure. Higher temperatures favor the growth of conjugated polyaromatic structures in the soot, a progression hypothesized to control the evolution from BrC to BC character of the emitted aerosols.</p>}},
  author       = {{Malmborg, Vilhelm and Eriksson, Axel and Gren, Louise and Török, Sandra and Shamun, Sam and Novakovic, Maja and Zhang, Yilong and Kook, Sanghoon and Tunér, Martin and Bengtsson, Per Erik and Pagels, Joakim}},
  issn         = {{0278-6826}},
  keywords     = {{Matti Maricq}},
  language     = {{eng}},
  number       = {{7}},
  pages        = {{769--784}},
  publisher    = {{Taylor & Francis}},
  series       = {{Aerosol Science and Technology}},
  title        = {{Characteristics of BrC and BC emissions from controlled diffusion flame and diesel engine combustion}},
  url          = {{http://dx.doi.org/10.1080/02786826.2021.1896674}},
  doi          = {{10.1080/02786826.2021.1896674}},
  volume       = {{55}},
  year         = {{2021}},
}