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| Titel |
Size-distributions of n-alkanes, PAHs and hopanes and their sources in the urban, mountain and marine atmospheres over East Asia |
| VerfasserIn |
G. Wang, K. Kawamura, M. Xie, S. Hu, S. Gao, J. Cao, Z. An, Z. Wang |
| 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 ; 9, no. 22 ; Nr. 9, no. 22 (2009-11-23), S.8869-8882 |
| Datensatznummer |
250007764
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| Publikation (Nr.) |
 copernicus.org/acp-9-8869-2009.pdf |
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| Zusammenfassung |
| Size-segregated (9 stages) n-alkanes, polycyclic aromatic
hydrocarbons (PAHs) and hopanes in the urban (Baoji city in inland China),
mountain (Mt. Tai in east coastal China) and marine (Okinawa Island, Japan)
atmospheres over East Asia were studied using a GC/MS technique. Ambient
concentrations of n-alkanes (1698±568 ng m−3 in winter and
487±145 ng m−3 in spring), PAHs (536±80 and 161±39 ng m−3),
and hopanes (65±24 and 20±2.4 ng m−3) in the
urban air are 1–2 orders of magnitude higher than those in the mountain
aerosols and 2–3 orders of magnitude higher than those in the marine
samples. Mass ratios of n-alkanes, PAHs and hopanes clearly demonstrate
coal-burning emissions as their major source. Size distributions of fossil
fuel derived n-alkane, PAHs and hopanes were found to be unimodal in most
cases, peaking at 0.7–1.1 μm size. In contrast, plant wax derived
n-alkanes presented a bimodal distribution with two peaks at the sizes of
0.7–1.1 μm and >4.7 μm in the summer mountain and spring
marine samples. Among the three types of samples, geometric mean diameter
(GMD) of the organics in fine mode (<2.1 μm) was found to be
smallest (av. 0.63 μm in spring) for the urban samples and largest
(1.01 μm) for the marine samples, whereas the GMD in coarse mode
(≥2.1 μm) was found to be smallest (3.48 μm) for the
marine aerosols and largest (4.04 μm) for the urban aerosols. The fine
mode GMDs of the urban and mountain samples were larger in winter than in
spring and summer. Moreover, GMDs of 3- and 4-ring PAHs were larger than
those of 5- and 6-ring PAHs in the three types of atmospheres. Such
differences in GMDs can be interpreted by the repartitioning of organic
compounds and the coagulation and hygroscopic growth of particles during a
long-range transport from the inland continent to the marine area, as well
as the difference in their sources among the three regions. |
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