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| Titel |
Determination of emissions from Mediterranean shrubland fires. |
| VerfasserIn |
Elisa Garcia-Hurtado, Esther Borrás, Pilar Sanchez, Teresa Vera, M. Jaime Baeza, V. Ramón Vallejo |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250051901
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| Zusammenfassung |
| Forest fires have been increasing during the last decades in the Mediterranean Basin,
significantly contributing to greenhouse gases (GHG) and aerosol emissions to the
atmosphere. More than 50% of these fires affect shrublands accumulating high fuel load. The
quantity and composition of emissions depend on burning conditions and on the composition
of fuels. In order to characterize the specific emissions from widely representative
Mediterranean shrublands, we conducted experimental burnings during April 2009 in
the Ayora valley (Valencia, Spain). In this paper we present an overview of the
experimental setup and main results obtained. Three 1000 m2 plots located on the
same slope and with the same type of vegetation were selected as representative
fire-prone Mediterranean shrublands for fire occurrence and as emission source.
Vegetation-fuel was characterized before burning. A meteorological tower was installed to
provide temperature, wind speed and humidity measurements during the experimental
burns.
The instrumentation used during the experiments was designed to obtain continuous
measurements, and to collect simultaneously samples in cartridges and high-volume filters at
ground level. Determination and quantification of the chemical compounds emitted, both in
gaseous and particulate phase, was carried out using GC-MS and LC-MS. We explored
the identification of biotracers from the two phases and compared with previous
studies.
The emission composition research was focused on acids, alcohols, aldehydes, ketones,
volatile organic compounds (VOC’s) and poliaromatic hydroacarbons (PAH’s). The main
compounds found were palmitic acid, glutaric acid, phthalic acid, levoglucosan, cresol,
glyoxal, methylglyoxal, butanone, pentanone, limonene, a-pinene, pirene and fluorantene.
The results were calculated in mass C/m3 to estimate a total mass of carbon sampled during
burning emissions. The range of concentration measured was in the order of microg/m3 for
each group of compounds.
The relationship between Mass Combustion Efficiency (MCE), fuel, moisture,
temperature and Emission Factors (EF) of CO2, CO and CH4 were established and the results
compared with similar studies. The identification of the two phases of the fire (flaming and
smoldering) was done comparing the ratio of the concentration CO2:CH4 and the temperature
profile of the fire. With this procedure, it was possible to separate the emissions during each
phase.
The maximum ground surface temperature reached was 700ºC and the total fire MCE was
lower than 90%.The MCE values for the flaming phase were comparable to wildfires data
from the literature, but lower for the smoldering phase.
The EF (CO2) in the flaming phase was around 1700 gCO2/kg dry matter and 1045
gCO2/kg dry matter for the smoldering phase. Total emission in the three replicates was 3.8
Kg CO2/m2 in flaming and 2.3 Kg CO2/m2 in smoldering.
This work provides new experimental data that would contribute to improve the emission
factors currently used in GHG inventories for Mediterranean countries, and to identify
characteristic trace compounds from shrubland fires. |
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