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| Titel |
Urban organic aerosols measured by single particle mass spectrometry in the megacity of London |
| VerfasserIn |
M. Dall'Osto, R. M. Harrison |
| 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 ; 12, no. 9 ; Nr. 12, no. 9 (2012-05-10), S.4127-4142 |
| Datensatznummer |
250011125
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| Publikation (Nr.) |
 copernicus.org/acp-12-4127-2012.pdf |
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| Zusammenfassung |
| During the month of October 2006, as part of the REPARTEE-I experiment
(Regent's Park and Tower Environmental Experiment) an Aerosol Time-Of-Flight
Mass Spectrometer (ATOFMS) was deployed at an urban background location in
the city of London, UK. Fifteen particle types were classified, some of which
were already discussed (Dall'Osto et al., 2009a,b; Harrison et al., 2012). In
this manuscript the origins and properties of four unreported particle types
postulated to be due to locally generated aerosols, independent of the air
mass type advected into London, are examined. One particle type, originating
from lubricating oil (referred to as Ca-EC), was associated with morning rush
hour traffic emissions. A second particle type, composed of both inorganic
and organic species (called Na-EC-OC), was found enhanced in particle number
concentration during evening time periods, and is likely to originate from a
source operating at this time of day, or more probably from condensation of
semi-volatile species. A third class, internally mixed with organic carbon
and sulphate (called OC), was found to spike both in the morning and evenings
although it could not unambiguously associated with a specific source or
atmospheric process. The fourth class (Secondary Organic Aerosols –
Polycyclic Aromatic Hydrocarbon; SOA-PAH) exhibited maximum frequency during
the warmest part of the day, and a number of factors point towards secondary
aerosol production from traffic-related volatile aromatic compounds. Single
particle mass spectra of this particle type showed an oxidized polycyclic
aromatic compound signature. A comparison of ATOFMS particle class data is
then made with factors obtained by Positive Matrix Factorization and PAH
signatures obtained from Aerosol Mass Spectrometer (AMS) data (Allan et al.,
2010). Both the Ca-EC and OC particle types correlate with primary
Hydrocarbon-like Organic Aerosol (HOA, R2 = 0.65 and 0.50
respectively), and Na-EC-OC correlates weakly with the AMS secondary
Oxygenated Organic Aerosol (OOA), (R2 = 0.35). Cluster SOA-PAH was
found not to correlate with any AMS signal. A detailed analysis was conducted
to identify ATOFMS particle type(s) representative of the AMS cooking aerosol
factor (COA), but no convincing associations were found. The combined ATOFMS
and AMS results of this REPARTEE study do not always provide an entirely
coherent interpretation. |
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