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| Titel |
A long term source apportionment study of wood burning and traffic aerosols for three measurement sites in Switzerland |
| VerfasserIn |
Hanna Herich, Christoph Hüglin, Brigitte Buchmann |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250033953
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| Zusammenfassung |
| Besides their effects on radiative forcing soot aerosols have been found to cause health effects
as they are carcinogenic. Diesel engines and incomplete biomass burning are the major
emission sources of soot particles. Especially during winter, the wood burning (WB)
emissions from residential heating have been found to contribute significantly to the total
carbonaceous material (CM). To investigate the contribution of fossil fuel (FF) and WB
emissions seven-wavelength aethalometers have been deployed in previous studies
(Sandradewi et al. 2008, Favez et al. 2009). In these studies, the stronger light absorption of
WB aerosols in the blue and ultraviolet compared to the light absorption of aerosols
from FF combustion was used. Linear regression modelling of CM against the light
absorption coefficient of FF combustion aerosols in the infrared (950Â nm) and the light
absorption coefficient of WB aerosols in the blue (470Â nm) was proposed for source
apportionment.
In this study we present long term aethalometer measurements at two rural and
one urban background measurement stations in Switzerland from 2008 - 2010. At
these stations organic (OC) and elemental carbon (EC) were also measured by
thermochemical analysis providing estimates for total CM. Above described linear
regession modelling was applied for determination of the contribution of FF and WB
emissions to total CM. Sensitivity tests for different regression models and for
varying light absorption exponents were performed. It was found that the regression
modelling approach is only limited suitable for long term datasets because of significant
fractions of CM resulting from sources and processes other than FF and WB. Thus in
a different approach we focused on black carbon (BC). The contribution of WB
and FF to BC was directly determined from the absorption coefficients of FF and
WB aerosols which were calculated with the use of absorption exponents taken
from literature. First results show that in winter the contribution of wood smoke
emissions to BC is ca. 23% at rural stations, during summer, the contribution of
WB aerosols to BC is negligible. The obtained WB contributions to BC correlate
well with measured concentrations of levoglucosan, a finding that supports this
approach.
References
J. Sandradewi, A.S.H. Prevot, S. Szidat, N. Perron, R. M. Alfarra, V. Lanz, E. Weingartner
and U. Baltensperger. Using aerosol light absorption measurements for the quantitative
determination of wood burning and traffic emission contributions to particulate matter.
Environmental Science & Technology, 42, 2008.
O. Favez, H. Cachier, J. Sciare, R. Sarda-Estève, and L. Martinon. Evidence for a significant
contribution of wood burning aerosols to PM2.5 during the winter season in Paris, France.
Atmospheric Environment, 43(22-23):3640-3644, 2009. |
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