Atmospheric mercury in the Southern Hemisphere – Part 1: Trend and inter-annual variations in atmospheric mercury at Cape Point, South Africa, in 2007–2017, and on Amsterdam Island in 2012–2017
<p>The Minamata Convention on Mercury (Hg) entered into force in 2017, committing its 116 parties (as of January 2019) to curb anthropogenic emissions. Monitoring of atmospheric concentrations and trends is an important part of the effectiveness evaluation of the convention. A few years ago (i...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-07-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/20/7683/2020/acp-20-7683-2020.pdf |
| Summary: | <p>The Minamata Convention on Mercury (Hg) entered into force in 2017,
committing its 116 parties (as of January 2019) to curb anthropogenic
emissions. Monitoring of atmospheric concentrations and trends is an
important part of the effectiveness evaluation of the convention. A few
years ago (in 2017) we reported an increasing trend in atmospheric Hg
concentrations at the Cape Point Global Atmosphere Watch (GAW) station in
South Africa (34.3535<span class="inline-formula"><sup>∘</sup></span> S, 18.4897<span class="inline-formula"><sup>∘</sup></span> E) for the 2007–2015 period. With 2 more years of
measurements at Cape Point and the 2012–2017 data from Amsterdam Island
(37.7983<span class="inline-formula"><sup>∘</sup></span> S, 77.5378<span class="inline-formula"><sup>∘</sup></span> E) in
the remote southern Indian Ocean, a more complex picture emerges: at Cape
Point the upward trend for the 2007–2017 period is still significant, but
no trend or a slightly downward trend was detected for the period 2012–2017
at both Cape Point and Amsterdam Island. The upward trend at Cape Point is
driven mainly by the Hg concentration minimum in 2009 and maxima in 2014 and
2012. Using ancillary data on <span class="inline-formula"><sup>222</sup>Rn</span>, CO, <span class="inline-formula">O<sub>3</sub></span>, <span class="inline-formula">CO<sub>2</sub></span>, and
<span class="inline-formula">CH<sub>4</sub></span> from Cape Point and Amsterdam Island, the possible reasons for the
trend and its change are investigated. In a companion paper this analysis is
extended for the Cape Point station by calculations of source and sink
regions using backward-trajectory analysis.</p> |
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| ISSN: | 1680-7316 1680-7324 |