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| Titel |
Field measurements of trace gases emitted by prescribed fires in southeastern US pine forests using an open-path FTIR system |
| VerfasserIn |
S. K. Akagi, I. R. Burling, A. Mendoza, T. J. Johnson, M. Cameron, D. W. T. Griffith, C. Paton-Walsh, D. R. Weise, J. Reardon, R. J. Yokelson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 1 ; Nr. 14, no. 1 (2014-01-08), S.199-215 |
| Datensatznummer |
250118252
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| Publikation (Nr.) |
 copernicus.org/acp-14-199-2014.pdf |
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| Zusammenfassung |
| We report trace-gas emission factors from three pine-understory prescribed
fires in South Carolina, US measured during the fall of 2011. The fires
were more intense than many prescribed burns because the fuels included
mature pine stands not subjected to prescribed fire in decades that were lit
following an extended drought. Emission factors were measured with a fixed
open-path Fourier transform infrared (OP-FTIR) system that was deployed on
the fire control lines. We compare these emission factors to those measured
with a roving, point sampling, land-based FTIR and an airborne FTIR deployed
on the same fires. We also compare to emission factors measured by a similar
OP-FTIR system deployed on savanna fires in Africa. The data suggest that
the method used to sample smoke can strongly influence the relative
abundance of the emissions that are observed. The majority of fire emissions
were lofted in the convection column and were sampled by the airborne FTIR.
The roving, ground-based, point sampling FTIR measured the contribution of
individual residual smoldering combustion fuel elements scattered throughout
the burn site. The OP-FTIR provided a ~ 30 m path-integrated
sample of emissions transported to the fixed path via complex ground-level
circulation. The OP-FTIR typically probed two distinct combustion regimes,
"flaming-like" (immediately after adjacent ignition and before the
adjacent plume achieved significant vertical development) and
"smoldering-like." These two regimes are denoted "early" and "late",
respectively. The path-integrated
sample of the ground-level smoke layer adjacent to the fire from the OP-FTIR
provided our best estimate of fire-line exposure to smoke for wildland fire
personnel. We provide a table of estimated fire-line exposures for numerous
known air toxics based on synthesizing results from several studies. Our
data suggest that peak exposures are more likely to challenge permissible
exposure limits for wildland fire personnel than shift-average (8 h)
exposures. |
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