Black Carbon Aerosol Size in Wild-, Prescribed-, and Agricultural-Fire Smoke

J. P. Schwarz; A. E. Perring; J. M. Katich; B. Mediavilla; A. J. Soja; E. M. Gargulinski; B. Weinzierl; R. H. Moore; H. S. Halliday; G. S. Diskin; J. B. Nowak; J. P. DiGangi

doi:10.1029/2025GL118939

Black Carbon Aerosol Size in Wild-, Prescribed-, and Agricultural-Fire Smoke

J. P. Schwarz (Corresponding author)
, A. E. Perring
, J. M. Katich
, B. Mediavilla
, A. J. Soja
, E. M. Gargulinski
, B. Weinzierl
, R. H. Moore
, H. S. Halliday
, G. S. Diskin
, J. B. Nowak
, J. P. DiGangi

Aerosol Physics and Environmental Physics

Publications: Contribution to journal › Article › Peer Reviewed

Abstract

Refractory black carbon (rBC), a primary aerosol material, is radiatively significant and a uniquely useful tracer of aerosol processes. Here we present analyses of open-burning generated rBC size distributions observed both from a research aircraft and from ground-based sampling. The aircraft sampled fresh smoke generated by 14 different western wildfires and 80 agricultural/prescribed fires, providing sufficient data for statistical analysis of rBC size. The ground-based observations represent a narrower range of smoke sources, but provide a constraint on contributions to total rBC concentrations from larger particles than those quantified from the aircraft. The range of rBC mass median diameter observed in log-normal fits was 0.11–0.2 μm volume-equivalent diameter, with geometric standard deviations ranging from 1.25 to 1.5. rBC size showed a dependence on fuel type. We hypothesize that fuel density and structure significantly influence rBC size in open burning emissions via their influence on the physical conditions of open burning.

Original language	English
Article number	e2025GL118939
Number of pages	9
Journal	Geophysical Research Letters
Volume	53
Issue number	9
DOIs	https://doi.org/10.1029/2025GL118939
Publication status	Published - 16 May 2026

Funding

We thank the pilots and crew of the NASA DC‐8 for their critical help in obtaining the data that made this analysis possible. We thank Dr. Nancy French for helpful discussion. The authors acknowledge generous support from the NOAA AC4 program for FIREX‐AQ. JMK was supported in part by NASA Earth Sciences Division, Upper Atmospheric Composition Program Grant NNH16ZDA001N. Finally, we acknowledge the contributions of two anonymous reviewers.

Austrian Fields of Science 2012

103039 Aerosol physics
103037 Environmental physics
105208 Atmospheric chemistry

Keywords

black carbon
fire emissions
firex-aq

Access to Document

10.1029/2025GL118939Licence: CC BY 4.0

Cite this

Schwarz, J. P., Perring, A. E., Katich, J. M., Mediavilla, B., Soja, A. J., Gargulinski, E. M., Weinzierl, B., Moore, R. H., Halliday, H. S., Diskin, G. S., Nowak, J. B., & DiGangi, J. P. (2026). Black Carbon Aerosol Size in Wild-, Prescribed-, and Agricultural-Fire Smoke. Geophysical Research Letters, 53(9), Article e2025GL118939. https://doi.org/10.1029/2025GL118939

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title = "Black Carbon Aerosol Size in Wild-, Prescribed-, and Agricultural-Fire Smoke",

abstract = "Refractory black carbon (rBC), a primary aerosol material, is radiatively significant and a uniquely useful tracer of aerosol processes. Here we present analyses of open-burning generated rBC size distributions observed both from a research aircraft and from ground-based sampling. The aircraft sampled fresh smoke generated by 14 different western wildfires and 80 agricultural/prescribed fires, providing sufficient data for statistical analysis of rBC size. The ground-based observations represent a narrower range of smoke sources, but provide a constraint on contributions to total rBC concentrations from larger particles than those quantified from the aircraft. The range of rBC mass median diameter observed in log-normal fits was 0.11–0.2 μm volume-equivalent diameter, with geometric standard deviations ranging from 1.25 to 1.5. rBC size showed a dependence on fuel type. We hypothesize that fuel density and structure significantly influence rBC size in open burning emissions via their influence on the physical conditions of open burning.",

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AU - Soja, A. J.

AU - Gargulinski, E. M.

AU - Weinzierl, B.

AU - Moore, R. H.

AU - Halliday, H. S.

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N2 - Refractory black carbon (rBC), a primary aerosol material, is radiatively significant and a uniquely useful tracer of aerosol processes. Here we present analyses of open-burning generated rBC size distributions observed both from a research aircraft and from ground-based sampling. The aircraft sampled fresh smoke generated by 14 different western wildfires and 80 agricultural/prescribed fires, providing sufficient data for statistical analysis of rBC size. The ground-based observations represent a narrower range of smoke sources, but provide a constraint on contributions to total rBC concentrations from larger particles than those quantified from the aircraft. The range of rBC mass median diameter observed in log-normal fits was 0.11–0.2 μm volume-equivalent diameter, with geometric standard deviations ranging from 1.25 to 1.5. rBC size showed a dependence on fuel type. We hypothesize that fuel density and structure significantly influence rBC size in open burning emissions via their influence on the physical conditions of open burning.

AB - Refractory black carbon (rBC), a primary aerosol material, is radiatively significant and a uniquely useful tracer of aerosol processes. Here we present analyses of open-burning generated rBC size distributions observed both from a research aircraft and from ground-based sampling. The aircraft sampled fresh smoke generated by 14 different western wildfires and 80 agricultural/prescribed fires, providing sufficient data for statistical analysis of rBC size. The ground-based observations represent a narrower range of smoke sources, but provide a constraint on contributions to total rBC concentrations from larger particles than those quantified from the aircraft. The range of rBC mass median diameter observed in log-normal fits was 0.11–0.2 μm volume-equivalent diameter, with geometric standard deviations ranging from 1.25 to 1.5. rBC size showed a dependence on fuel type. We hypothesize that fuel density and structure significantly influence rBC size in open burning emissions via their influence on the physical conditions of open burning.

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Black Carbon Aerosol Size in Wild-, Prescribed-, and Agricultural-Fire Smoke

Abstract

Funding

Austrian Fields of Science 2012

Keywords

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