Mercury Emissions: The Global Context
Mercury emissions are a global problem that knows no national or continental boundaries. Mercury that is emitted to the air can travel thousands of miles in the atmosphere before it is eventually deposited back to the earth in rainfall or in dry gaseous form.
Natural sources of mercury include volcanic eruptions and emissions from the ocean. Anthropogenic (human-caused) emissions include mercury that is released from fuels or raw materials, or from uses in products or industrial processes.
Some of the mercury circulating through today's environment was released years ago. Land, water, and other surfaces can repeatedly re-emit mercury into the atmosphere after its initial release into the environment. We know that anthropogenic emissions continue to add significantly to the global pool of mercury.
In the U.S. and globally, coal combustion is the largest source of anthropogenic mercury emissions. Other large sources of emissions are artisanal and small-scale gold mining (ASGM), non-ferrous metals production, and cement production. (United Nations Environment Programme (UNEP), The Global Atmospheric Mercury Assessment: Sources, Emissions and Transport, Geneva, 2008).
Estimated proportion of global anthropogenic mercury emissions in 2005 from different sources.
Total = 1930 metric tons. ASGM = Artisanal and Small Scale Gold Mining.
Source: United Nations Environment Programme (UNEP), The Global Atmospheric Mercury Assessment: Sources, Emissions and Transport, 2008.
How much mercury is emitted worldwide each year? Recent estimates of annual global mercury emissions from both natural and anthropogenic sources are in the range of 5,000 to 8,000 metric tons per year. These estimates include mercury that is re-emitted. The world map and the bar graph below provide information about the worldwide distribution of anthropogenic mercury emissions.
The U.S. is the third largest emitter of anthropogenic mercury.
Global distribution of anthropogenic mercury emissions to air in 2005
Source: United Nations Environment Programme Global Atmospheric Mercury Assessment: Sources, Emissions and Transport, 2008, using 2005 data, as presented by the Arctic Monitoring and Assessment Programme Secretariat
Anthropogenic mercury emissions from different regions from 1990-2005
Source: AMAP / Wilson et al., 2010. Updating Historical Global Inventories of Anthropogenic Mercury Emissions to Air. AMAP Technical Report No. 3 (2010), Arctic Monitoring and Assessment Program (AMAP), Oslo, Norway (PDF). (12 pp, 445 K, About PDF Files)
- For more information on regulatory and policy measures that EPA is taken to reduce mercury pollution, see the EPA Mercury Portal.
- Learn about EPA's International Actions Reducing Mercury Emissions and Use.
For additional information on EPA's work with mercury, contact:
U.S. Environmental Protection Agency
Office of International and Tribal Affairs (2670R)
1200 Pennsylvania Ave., NW
Washington, DC 20460