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Titel |
Correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China |
VerfasserIn |
X. W. Fu, H. Zhang, C.-J. Lin, X. B. Feng, L. X. Zhou, S. X. Fang |
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 ; 15, no. 2 ; Nr. 15, no. 2 (2015-01-29), S.1013-1028 |
Datensatznummer |
250119352
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Publikation (Nr.) |
copernicus.org/acp-15-1013-2015.pdf |
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Zusammenfassung |
Correlation analyses between atmospheric mercury (Hg) and
other trace gases are useful for identification of sources and constraining
regional Hg emissions. Emissions of Hg in Asia contribute significantly to
the global budget of atmospheric Hg. However, due to the lack of reliable
data on the source strength, large uncertainties remain in the emission
inventories of Hg in Asia. In the present study, we calculated the
correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 for mainland
China, South Asia, the Indochinese Peninsula, and Central Asia using the
ground-based observations at three remote sites in northwestern and southwestern
China, and applied these values to estimate GEM emissions in the four source
regions. The geometric mean GEM / CO correlation slopes for mainland China,
South Asia, the Indochinese Peninsula, and Central Asia were 7.3 ± 4.3,
7.8 ± 6.4, 7.8 ± 5.0, and 13.4 ± 9.5 pg m−3 ppb−1,
respectively, and values in the same source regions were 33.3 ± 30.4,
27.4 ± 31.0, 23.5 ± 15.3, and 20.5 ± 10.0 pg m−3 ppb−1 for
the GEM / CH4 correlation slopes, respectively. The geometric means of
GEM / CO2 correlation slopes for mainland China, South Asia, and Central
Asia were 240 ± 119, 278 ± 164, 315 ± 289 pg m−3 ppm−1,
respectively. These values were the first reported correlation slopes of
GEM / CO, GEM / CO2, and GEM / CH4 in four important source regions of
Asia, not including the GEM / CO ratios in mainland China. The correlation slopes of
GEM / CO, GEM / CO2, and GEM / CH4 in Asia were relatively higher than
those observed in Europe, North America, and South Africa, which may
highlight GEM emissions from non-ferrous smelting, large-scale and artisanal
mercury and gold production, natural sources, and historically deposited
mercury (re-emission) in Asia. Using the observed GEM / CO and GEM / CO2
slopes, and the recently reported emission inventories of CO and CO2,
the annual GEM emissions in mainland China, South Asia, the Indochinese
Peninsula, and Central Asia were estimated to be in the ranges of
1071–1187, 340–470, 125, and 54–90 t, respectively. The estimated
quantity of GEM emissions from the GEM / CH4 correlation slopes is
significantly larger, which may be due to the larger uncertainties in
CH4 emissions in Asia as well as insufficient observations of
GEM / CH4 correlation slopes, therefore leading to an overestimate of GEM
emissions. Our estimates of GEM emissions in the four Asian regions were
significantly higher (3–4 times) than the anthropogenic GEM emissions
reported in recent studies. This discrepancy could come from a combination
of reasons including underestimates of anthropogenic and natural GEM
emissions; large uncertainties related to CO, CO2, and CH4
emission inventories; and inherent limitations of the correlation slope
method. |
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