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| Titel |
Spatial variation of chemical composition and sources of submicron aerosol in Zurich during wintertime using mobile aerosol mass spectrometer data |
| VerfasserIn |
C. Mohr, Rene Richter, P. F. DeCarlo, A. S. H. Prévôt, U. Baltensperger |
| 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 ; 11, no. 15 ; Nr. 11, no. 15 (2011-08-01), S.7465-7482 |
| Datensatznummer |
250009956
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| Publikation (Nr.) |
 copernicus.org/acp-11-7465-2011.pdf |
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| Zusammenfassung |
| Mobile measurements of PM1 (particulate matter with an aerodynamic
diameter <1 μm) chemical composition using a quadrupole aerosol mass
spectrometer and a multi-angle absorption photometer were performed using
the PSI mobile laboratory during winter 2007/2008 and December 2008 in the
metropolitan area of Zurich, Switzerland. Positive matrix factorization
(PMF) applied to the organic fraction of PM1 yielded 3 factors:
Hydrocarbon-like organic aerosol (HOA) related to traffic emissions; organic
aerosol from wood burning for domestic heating purposes (WBOA); and
oxygenated organic aerosol (OOA), assigned to secondary organic aerosol
formed by oxidation of volatile precursors. The chemical composition of
PM1 was assessed for an urban background site and various sites
throughout the city. The background site is dominated by secondary inorganic
and organic species (57 %), BC, HOA, and WBOA account for 15 %, 6 %,
and 12 %, respectively. As for the other sites, HOA is important along
major roads (varying between 7 and 14 % of PM1 for different sites
within the city, average all sites 8 %), domestic wood burning makes up
between 8–15 % of PM1 for different sites within the city (average
all sites 10.5 %). OOA makes up the largest fraction of organic aerosol
(44 % on average). A new method allows for the separation and
quantification of the local fraction of PM1 emitted or rapidly formed
in the city, and the fraction of PM1 originating from the urban
background. The method is based on simultaneous on-road mobile and
stationary background measurements and the correction of small-scale
meteorological effects using the ratio of on-road sulfate to stationary
sulfate. Especially during thermal inversions over the Swiss plateau, urban
background concentrations contribute substantially to particulate number
concentrations (between 40 and 80 % depending on meteorological conditions
and emissions, 60 % on average) as well as to the mass concentrations of
PM1 components measured on road in downtown Zurich (between 30 and
90 %, on average 60 % for black carbon and HOA, and between 90 and
100 % for WBOA, OOA, and the measured inorganic components). The results
emphasize, on a scientific level, the advantage of mobile measurements for
distinguishing local from regional air pollution research, and on a
political level, the importance of regional collaboration for mitigating air
pollution issues. |
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