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| Titel |
Secondary organic aerosol formation from photochemical aging of light-duty gasoline vehicle exhausts in a smog chamber |
| VerfasserIn |
T. Liu, X. Wang, W. Deng, Q. Hu, X. Ding, Y. Zhang, Q. He, Z. Zhang, S. Lu, X. Bi, J. Chen, J. Yu |
| 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 ; 15, no. 15 ; Nr. 15, no. 15 (2015-08-14), S.9049-9062 |
| Datensatznummer |
250119966
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| Publikation (Nr.) |
 copernicus.org/acp-15-9049-2015.pdf |
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| Zusammenfassung |
| In China, a rapid increase in passenger vehicles has led to the growing
concern of vehicle exhaust as an important source of anthropogenic secondary
organic aerosol (SOA) in megacities hard hit by haze. In this study, the SOA
formation of emissions from two idling light-duty gasoline vehicles (LDGVs)
(Euro 1 and Euro 4) operated in China was investigated in a 30 m3 smog
chamber. Five photo-oxidation experiments were carried out at 25 °C
with relative humidity at around 50 %. After aging at an OH exposure of
5 × 106 molecules cm−3 h, the formed SOA was 12–259
times as high as primary organic aerosol (POA). The SOA production factors
(PF) were 0.001–0.044 g kg−1 fuel, comparable with those from the
previous studies at comparable OH exposure. This quite lower OH exposure than
that in typical atmospheric conditions might however lead to the
underestimation of the SOA formation potential from LDGVs. Effective SOA
yields in this study were well fit by a one-product gas-particle partitioning
model but quite lower than those of a previous study investigating SOA
formation from three idling passenger vehicles (Euro 2–4). Traditional
single-ring aromatic precursors and naphthalene could explain 51–90 % of
the formed SOA. Unspeciated species such as branched and cyclic alkanes might
be the possible precursors for the unexplained SOA. A high-resolution
time-of-flight aerosol mass spectrometer was used to characterize the
chemical composition of SOA. The relationship between f43 (ratio of
m/z 43, mostly C2H3O+, to the total signal in mass spectrum)
and f44 (mostly CO2+) of the gasoline vehicle exhaust SOA is
similar to the ambient semi-volatile oxygenated organic aerosol (SV-OOA). We
plot the O : C and H : C molar ratios of SOA in a Van Krevelen diagram.
The slopes of ΔH : C / ΔO : C ranged from −0.59 to
−0.36, suggesting that the oxidation chemistry in these experiments was a
combination of carboxylic acid and alcohol/peroxide formation. |
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