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| Titel |
Characterization and source apportionment of atmospheric organic and elemental carbon during fall and winter of 2003 in Xi'an, China |
| VerfasserIn |
J. J. Cao, F. Wu, J. C. Chow, S. C. Lee, Y. Li, S. W. Chen, Z. S. An, K. K. Fung, J. G. Watson, C. S. Zhu, S. X. Liu |
| 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 ; 5, no. 11 ; Nr. 5, no. 11 (2005-11-22), S.3127-3137 |
| Datensatznummer |
250003154
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| Publikation (Nr.) |
 copernicus.org/acp-5-3127-2005.pdf |
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| Zusammenfassung |
| Continuous measurements of atmospheric organic and elemental carbon (OC and
EC) were taken during the high-pollution fall and winter seasons at Xi'an,
Shaanxi Province, China from September 2003 through February 2004.
Battery-powered mini-volume samplers collected PM2.5 samples daily and
PM10 samples every third day. Samples were also obtained from the
plumes of residential coal combustion, motor-vehicle exhaust, and biomass
burning sources. These samples were analyzed for OC/EC by thermal/optical
reflectance (TOR) following the Interagency Monitoring of Protected Visual
Environments (IMPROVE) protocol. OC and EC levels at Xi'an are higher than
most urban cities in Asia. Average PM2.5 OC concentrations in fall and
winter were 34.1±18.0 μg m−3 and 61.9±;33.2 μg m−3,
respectively; while EC concentrations were 11.3±6.9 μg m−3
and 12.3±5.3 μg m−3, respectively. Most of the OC
and EC were in the PM2.5 fraction. OC was strongly correlated (R>0.95)
with EC in the autumn and moderately correlated (R=0.81) with EC
during winter. Carbonaceous aerosol (OC×1.6+EC) accounted for
48.8%±10.1% of the PM2.5 mass during fall and 45.9±7.5%
during winter. The average OC/EC ratio was 3.3 in fall and 5.1 in
winter, with individual OC/EC ratios nearly always exceeding 2.0. The higher
wintertime OC/EC corresponded to increased residential coal combustion for
heating. Total carbon (TC) was associated with source contributions using
absolute principal component analysis (APCA) with eight thermally-derived
carbon fractions. During fall, 73% of TC was attributed to gasoline
engine exhaust, 23% to diesel exhaust, and 4% to biomass burning.
During winter, 44% of TC was attributed to gasoline engine exhaust,
44% to coal burning, 9% to biomass burning, and 3% to diesel engine
exhaust. |
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