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| Titel |
Source apportionment of submicron organic aerosols at an urban site by factor analytical modelling of aerosol mass spectra |
| VerfasserIn |
V. A. Lanz, M. R. Alfarra, U. Baltensperger, B. Buchmann, C. Hueglin, A. S. H. Prévôt |
| 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 ; 7, no. 6 ; Nr. 7, no. 6 (2007-03-20), S.1503-1522 |
| Datensatznummer |
250004825
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| Publikation (Nr.) |
 copernicus.org/acp-7-1503-2007.pdf |
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| Zusammenfassung |
| Submicron ambient aerosol was characterized in summer 2005 at an
urban background site in Zurich, Switzerland, during a three-week
measurement campaign. Highly time-resolved samples of non-refractory
aerosol components were analyzed with an Aerodyne aerosol mass
spectrometer (AMS). Positive matrix factorization (PMF) was used for
the first time for aerosol mass spectra to identify the main
components of the total organic aerosol and their sources. The PMF
retrieved factors were compared to measured reference mass spectra
and were correlated with tracer species of the aerosol and gas phase
measurements from collocated instruments. Six factors were found to
explain virtually all variance in the data and could be assigned
either to sources or to aerosol components such as oxygenated
organic aerosol (OOA). Our analysis suggests that at the measurement
site only a small (<10%) fraction of organic PM1 originates
from freshly emitted fossil fuel combustion. Other primary sources
identified to be of similar or even higher importance are
charbroiling (10–15%) and wood burning (~10%). The fraction
of all identified primary sources is considered as primary organic
aerosol (POA). This interpretation is supported by calculated ratios
of the modelled POA and measured primary pollutants such as
elemental carbon (EC), NOx, and CO, which are in good
agreement to literature values. A high fraction (60–69%) of the
measured organic aerosol mass is OOA which is interpreted mostly as
secondary organic aerosol (SOA). This oxygenated organic aerosol can
be separated into a highly aged fraction, OOA I, (40–50%) with low
volatility and a mass spectrum similar to fulvic acid, and a more
volatile and probably less processed fraction, OOA II (on average
20%). This is the first publication of a multiple component
analysis technique to AMS organic spectral data and also the first
report of the OOA II component. |
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