93 research outputs found
Current and future levels of mercury atmospheric pollution on a global scale
An assessment of current and future emissions, air
concentrations, and atmospheric deposition of mercury worldwide is presented
on the basis of results obtained during the performance of the EU GMOS
(Global Mercury Observation System) project. Emission estimates for mercury
were prepared with the main goal of applying them in models to assess
current (2013) and future (2035) air concentrations and atmospheric
deposition of this contaminant. The combustion of fossil fuels (mainly coal) for energy and heat
production in power plants and in industrial and residential boilers, as well as artisanal and small-scale gold mining, is one of the
major anthropogenic sources of Hg emissions to the atmosphere at present.
These sources account for about 37 and 25 % of the total anthropogenic
Hg emissions globally, estimated to be about 2000 t. Emissions in
Asian countries, particularly in China and India, dominate the total
emissions of Hg. The current estimates of mercury emissions from natural
processes (primary mercury emissions and re-emissions), including mercury
depletion events, were estimated to be 5207 t year<sup>−1</sup>, which
represents nearly 70 % of the global mercury emission budget. Oceans are the most
important sources (36 %), followed by biomass burning (9 %). A comparison
of the 2035 anthropogenic emissions estimated for three different scenarios with
current anthropogenic emissions indicates a reduction of these emissions in
2035 up to 85 % for the best-case scenario.
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Two global chemical transport models (GLEMOS and ECHMERIT) have been used
for the evaluation of future mercury pollution levels considering future
emission scenarios. Projections of future changes in mercury deposition on a
global scale simulated by these models for three anthropogenic emissions
scenarios of 2035 indicate a decrease in up to 50 % deposition in the
Northern Hemisphere and up to 35 % in Southern Hemisphere for the best-case scenario.
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The EU GMOS project has proved to be a very important research instrument
for supporting the scientific justification for the Minamata
Convention and monitoring of the implementation of targets of this
convention, as well as the EU Mercury Strategy. This project provided the
state of the art with regard to the development of the latest emission
inventories for mercury, future emission scenarios, dispersion modelling of
atmospheric mercury on a global and regional scale, and source–receptor
techniques for mercury emission apportionment on a global scale
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