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Titel |
Secondary organic aerosol formation from idling gasoline passenger vehicle emissions investigated in a smog chamber |
VerfasserIn |
E. Z. Nordin, A. C. Eriksson, P. Roldin, P. T. Nilsson, J. E. Carlsson, M. K. Kajos, H. Hellén, C. Wittbom, J. Rissler, J. Löndahl, E. Swietlicki, B. Svenningsson, M. Bohgard, M. Kulmala , M. Hallquist, J. H. Pagels |
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 ; 13, no. 12 ; Nr. 13, no. 12 (2013-06-28), S.6101-6116 |
Datensatznummer |
250018723
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Publikation (Nr.) |
copernicus.org/acp-13-6101-2013.pdf |
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Zusammenfassung |
Gasoline vehicles have recently been pointed out as potentially the main
source of anthropogenic secondary organic aerosol (SOA) in megacities.
However, there is a lack of laboratory studies to systematically investigate
SOA formation in real-world exhaust. In this study, SOA formation from pure
aromatic precursors, idling and cold start gasoline exhaust from three
passenger vehicles (EURO2–EURO4) were investigated with photo-oxidation
experiments in a 6 m3 smog chamber. The experiments were carried out
down to atmospherically relevant organic aerosol mass concentrations. The
characterization instruments included a high-resolution aerosol mass
spectrometer and a proton transfer mass spectrometer. It was found that
gasoline exhaust readily forms SOA with a signature aerosol mass spectrum
similar to the oxidized organic aerosol that commonly dominates the organic
aerosol mass spectra downwind of urban areas. After a cumulative OH exposure of
~5 × 106 cm−3 h, the formed SOA was 1–2 orders of
magnitude higher than the primary OA emissions. The SOA mass spectrum from a
relevant mixture of traditional light aromatic precursors gave f43
(mass fraction at m/z = 43), approximately
two times higher than to the gasoline SOA. However O : C and H : C ratios were
similar for the two cases. Classical C6–C9 light aromatic
precursors were responsible for up to 60% of the formed SOA, which is
significantly higher than for diesel exhaust. Important candidates for
additional precursors are higher-order aromatic compounds such as C10
and C11 light aromatics, naphthalene and methyl-naphthalenes. We conclude
that approaches using only light aromatic precursors
give an incomplete picture of the magnitude of SOA formation and the SOA
composition from gasoline exhaust. |
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