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Titel |
Observations of OM/OC and specific attenuation coefficients (SAC) in ambient fine PM at a rural site in central Ontario, Canada |
VerfasserIn |
T. W. Chan, L. Huang, W. R. Leaitch, S. Sharma, J. R. Brook, J. G. Slowik, J. P. D. Abbatt, P. C. Brickell, J. Liggio, S.-M. Li, H. Moosmüller |
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 ; 10, no. 5 ; Nr. 10, no. 5 (2010-03-09), S.2393-2411 |
Datensatznummer |
250008176
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Publikation (Nr.) |
copernicus.org/acp-10-2393-2010.pdf |
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Zusammenfassung |
Ambient particulate matter (PM) samples were collected on quartz filters at
a rural site in central Ontario during an intensive study in 2007. The
concentrations of organic carbon (OC), pyrolysis organic carbon (POC), and
elemental carbon (EC) were determined by thermal analysis. The
concentrations are compared to the organic aerosol mass concentration (OM)
measured with an Aerodyne C-ToF Aerosol Mass Spectrometer (AMS) and to the
particle absorption coefficient (basp) obtained from a Radiance
Research Particle Soot Absorption Photometer (PSAP). The total organic mass
to organic carbon ratios (OM/OC) and specific attenuation coefficients (SAC=basp/EC)
are derived. Proportionality of the POC mass with the oxygen
mass in the aerosols estimated from the AMS offers a potential means to
estimate OM/OC from thermal measurements only. The mean SAC for the study is
3.8±0.3 m2 g−1. It is found that the SAC is independent of or
decrease with increasing particle mass loading, depending on whether or not
the data are separated between aerosols dominated by more recent
anthropogenic input and aerosols dominated by longer residence time or
biogenic components. There is no evidence to support an enhancement of light
absorption by the condensation of secondary material to particles,
suggesting that present model simulations built on such an assumption may
overestimate atmospheric warming by BC. |
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