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| Titel |
Long-range transport of Asian dust and air pollutants to Taiwan: observed evidence and model simulation |
| VerfasserIn |
C.-Y. Lin, Z. Wang, W.-N. Chen, S.-Y. Chang, C. C. K. Chou, N. Sugimoto, X. Zhao |
| 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 ; 7, no. 2 ; Nr. 7, no. 2 (2007-01-24), S.423-434 |
| Datensatznummer |
250004467
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| Publikation (Nr.) |
 copernicus.org/acp-7-423-2007.pdf |
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| Zusammenfassung |
| Long-range transport of Asian dust and air pollutants are major
environmental concerns of Taiwan during the winter monsoon season when
northeasterly winds prevail following passages of cold fronts. Based on
hourly measurements of Taiwan Environmental Protection Administration (TEPA)
air quality monitoring stations, Lidar and in-situ IC, a significant
long-range transport dust and air pollutants event on 18 March 2005 has been
identified. During this episode, drastically elevated concentrations of
PM10, CO and SO2 along with the strong northeasterly on 18 March
were observed over background Wanli station, with peaks of about 170 μgm−3,
1.0 ppm and 14 ppb, respectively. We have found that air masses
of air pollutants and Asian dust are transported separately. Although the
mixing takes place on the way to Taiwan, it mixes slightly when they arrived
in Taiwan. The major component of the first PM10 peak were air
pollutants, evidenced by the consistent peaks of SO42− and
NO3 measured by in-situ IC, while no significant depolarization
was measured by Lidar. In contrast, the evident non-spherical particles and
hourly PM10 concentration consistently varied with Ca2+ indicating
that mineral dust was the major component of the second peak. Trajectory
analysis showed that these two peaks come from quite different sources
areas. The air masses of the first peak mainly come from anthropogenic area
and transport in the low boundary layer (<1500 m) while the masses of the
second peak originate from high altitude (>4000 m) of desert areas.
Numerical results showed significant agreement of temporal and vertical
variation of aerosol concentration with observations. The phenomena of split
air parcels between air pollutants and Asian dust transported to Taiwan are
strongly associated with the transport paths and stable and dry atmospheric
boundary conditions. |
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