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| Titel |
Characteristics of atmospheric Total Gaseous Mercury (TGM) observed in urban Nanjing, China |
| VerfasserIn |
J. Zhu, T. Wang, R. Talbot, H. Mao, C. B. Hall, X. Yang, C. Fu, B. Zhuang, S. Li, Y. Han, X. Huang |
| 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 ; 12, no. 24 ; Nr. 12, no. 24 (2012-12-20), S.12103-12118 |
| Datensatznummer |
250011681
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| Publikation (Nr.) |
 copernicus.org/acp-12-12103-2012.pdf |
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| Zusammenfassung |
| Long-term continuous measurements of total gaseous mercury (TGM = gaseous
elemental mercury (GEM) + reactive gaseous mercury (RGM)) were conducted
simultaneously along with meteorological variables and a suite of trace
gases at an urban site in Nanjing, China from 18 January to 31 December
2011. Measurements were conducted using a high resolution mercury vapor
analyzer (Tekran 2537B) with 5-min time resolution. The average
concentration of TGM was 7.9 ± 7.0 ng m−3 with a range of
0.8–180 ng m−3 over the study period. TGM concentrations followed a typical
lognormal pattern dominated by a range of 3–7 ng m−3, which was
significantly higher than the continental background values
(~1.5 ng m−3) in Northern Hemisphere. The mean seasonal TGM concentrations
decreased in the following order: summer, spring, fall, and winter. This
seasonal pattern was quite different from measurements at most other sites
around the world. We attributed high monthly average concentrations to the
re-volatilization of deposited mercury during the warm season due to high
temperatures and greater solar radiation. Previous modeling studies
suggested that Nanjing and the surrounding region have the largest Chinese
natural emissions during the summer. Positive correlations between
temperature, solar radiation, and TGM concentration combined with no
correlation between CO and TGM in summer provide a strong indication that
natural sources are important in Nanjing while most sharp peaks were caused
by anthropogenic sources. TGM concentrations in Nanjing exhibited a
noticeable diurnal pattern with a sharp increase after sunrise and peak of
greater than 8 ng m−3 during 7–10 a.m. local time. Further,
seasonally averaged diurnal cycles of TGM exhibited considerably different
patterns with the largest variation in spring and insignificant fluctuations
in winter. Using HYSPLIT backwards trajectories from six clusters, it was
indicated that the highest TGM concentrations, 11.9 ng m−3, was derived
from local air masses. The cleanest air masses, with an average TGM
concentration of 4.7 and 5.9 ng m−3, were advected from the north via
fast transport facilitated by sweeping synoptic flows. |
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