Current and future levels of mercury atmospheric pollution on a global scale
- 1NILU – Norwegian Institute for Air Research, Instituttveien 18, P.O. Box 100, 2027 Kjeller, Norway
- 2Meteorological Synthesizing Centre – East of EMEP, 2nd Roshchinsky proezd, 8/5, office 207, 115419 Moscow, Russia
- 3CNR – Institute of Atmospheric Pollution Research, Division of Rende, UNICAL-Polifunzionalie, Rende 87036, Italy
- 4University of Groningen, Arctic Centre, Aweg 30, 9718 CW Groningen, the Netherlands
- 5CNR – Institute of Atmospheric Pollution Research, Area della Ricerca Roma 1, Via Salaria Km 29 300, 00015 Monterotondo (Rome), Italy
- 6AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow, Poland
- 7IVL Swedish Environmental Research Institute, P.O. Box 53201, 400 14 Gothenburg, Sweden
Abstract. 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−1, 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.
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.
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.