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| Titel |
Atmospheric mercury concentration and chemical speciation at a rural site in Beijing, China: implications of mercury emission sources |
| VerfasserIn |
L. Zhang, S. X. Wang, L. Wang, J. M. Hao |
| 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. 20 ; Nr. 13, no. 20 (2013-10-30), S.10505-10516 |
| Datensatznummer |
250085775
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| Publikation (Nr.) |
 copernicus.org/acp-13-10505-2013.pdf |
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| Zusammenfassung |
| Continuous measurements of atmospheric mercury concentration and speciation
play a key role in identifying mercury sources and its behavior in the
atmosphere. In this study, speciated atmospheric mercury including gaseous
elemental mercury (GEM), reactive gaseous mercury (RGM) and particle-bound
mercury (PBM) were continuously measured at Miyun, a rural site in Beijing,
China, from December 2008 to November 2009. The average GEM, RGM and PBM
concentrations were found to be 3.22 ± 1.74, 10.1 ± 18.8 and
98.2 ± 112.7 pg m−3, respectively, about 2–20 times higher than
the background concentration of the Northern Hemisphere. The results
indicated that atmospheric mercury concentrations in northern China were
highly affected by anthropogenic emissions. The atmospheric mercury showed
obvious seasonal variations, with the highest seasonal average GEM
concentration in summer (3.48 ng m−3) and the lowest value in winter
(2.66 ng m−3). In autumn and winter a diurnal variation of GEM was
observed, with peak levels in the late afternoon till midnight. Most of the
high RGM concentration values occurred in the afternoon of all seasons due to
the higher oxidation. The PBM concentration was higher in early morning of all
seasons because of the the temperature inversion that increases in depth as the
night proceeds. The ratio of GEM to CO indicates that
residential boilers play an important role in the elevation of GEM in winter.
The ratio of RGM to O3 could be an indicator of the contribution of
local primary sources. The ratio of PBM to PM2.5 reveals that the air
mass from the east and southwest of the site in spring and summer carries
more atmospheric mercury. The HYSPLIT back-trajectory analysis indicated that
the monitoring site is affected by local, regional and interregional sources
simultaneously during heavy pollution episodes. The results from the
potential source contribution function (PSCF) model indicate that the
atmospheric transport predominantly from the northwest contributes to the
elevated atmospheric mercury in winter and autumn, while the North China
Plain (NCP) region and the northern part of the Yangtze River Delta (YRD)
region are the major source areas for mercury pollution in spring and summer. |
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