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| Titel |
Emissions of mercury in southern Africa derived from long-term observations at Cape Point, South Africa |
| VerfasserIn |
E.-G. Brunke, R. Ebinghaus, H. H. Kock, C. Labuschagne, F. Slemr |
| 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. 16 ; Nr. 12, no. 16 (2012-08-17), S.7465-7474 |
| Datensatznummer |
250011397
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| Publikation (Nr.) |
 copernicus.org/acp-12-7465-2012.pdf |
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| Zusammenfassung |
| Mercury emissions in South Africa have so far been estimated only by a
bottom-up approach from activities and emission factors for different
processes. In this paper we derive GEM/CO (GEM being gaseous elemental
mercury, Hg0), GEM/CO2, GEM/CH4, CO/CO2,
CH4/CO2, and CH4/CO emission ratios from plumes observed
during long-term monitoring of these species at Cape Point between March 2007
and December 2009. The average observed GEM/CO, GEM/CO2, GEM/CH4,
CO/CO2, CH4/CO2, and CH4/CO emission ratios were
2.40 ± 2.65 pg m−3 ppb−1 (n = 47),
62.7 ± 80.2 pg m−3 ppm−1 (n = 44),
3.61 ± 4.66 pg m−3 ppb−1 (n = 46),
35.6 ± 25.4 ppb ppm−1 (n = 52),
20.2 ± 15.5 ppb ppm−1 (n = 48), and
0.876 ± 1.106 ppb ppb−1 (n = 42), respectively. The observed
CO/CO2, CH4/CO2, and CH4/CO emission ratios agree within
the combined uncertainties of the observations and emissions with the ratios
calculated from EDGAR (version 4.2) CO2, CO, and CH4 inventories
for South Africa and southern Africa (South Africa, Lesotho, Swaziland,
Namibia, Botswana, Zimbabwe, and Mozambique) in 2007 and 2008 (inventories
for 2009 are not available yet). Total elemental mercury emission of 13.1,
15.2, and 16.1 t Hg yr−1 are estimated independently using the
GEM/CO, GEM/CO2, and GEM/CH4 emission ratios and the annual mean
CO, CO2, and CH4 emissions, respectively, of South Africa in 2007
and 2008. The average of these independent estimates of 14.8 t GEM yr−1
is much less than the total emission of 257 t Hg yr−1 shown by older
inventories which are now considered to be wrong. Considering the
uncertainties of our emission estimate, of the emission inventories, and the
fact that emission of GEM represents 50–78 % of all mercury emissions, our
estimate is comparable to the currently cited GEM emissions in 2004 and
somewhat smaller than emissions in 2006. A further increase of mercury
emissions due to increasing electricity consumption will lead to a more
pronounced difference. A quantitative assessment of the difference and its
significance, however, will require emission inventories for the years of
observations (2007–2009) as well as better data on the speciation of the
total mercury emissions in South Africa. |
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