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Atmospheric mysteries unraveling
http://www.colorado.edu/news/releases/2015/06/29/atmospheric-mysteries-unraveling[font face=Serif][font size=5]Atmospheric mysteries unraveling[/font]
June 29, 2015 • Cooperative Institute for Research in Environmental Science (CIRES)
[font size=3]It’s been difficult to explain patterns of toxic mercury in some parts of the world, such as why there’s so much of the toxin deposited into ecosystems from the air in the southeastern United States, even upwind of usual sources.
A new analysis led by researchers at the University of Colorado Boulder shows that one key to understanding mercury’s strange behavior may be the unexpected reactivity of naturally occurring halogen compounds from the ocean.
“Atmospheric chemistry involving bromine and iodine is turning out to be much more vigorous than we expected,” said CU-Boulder atmospheric chemist Rainer Volkamer, the corresponding author of the new paper published in the Proceedings of the National Academy of Sciences. “These halogen reactions can turn mercury into a form that can rain out of the air onto the ground or into oceans” up to 3.5 times faster than previously estimated, he said.
The new chemistry that Volkamer and his colleagues have uncovered, with the help of an innovative instrument developed at CU-Boulder, may also help scientists better understand a longstanding limitation of global climate models. Those models have difficulty explaining why levels of ozone, a greenhouse gas, were so low before the Industrial Revolution.
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June 29, 2015 • Cooperative Institute for Research in Environmental Science (CIRES)
[font size=3]It’s been difficult to explain patterns of toxic mercury in some parts of the world, such as why there’s so much of the toxin deposited into ecosystems from the air in the southeastern United States, even upwind of usual sources.
A new analysis led by researchers at the University of Colorado Boulder shows that one key to understanding mercury’s strange behavior may be the unexpected reactivity of naturally occurring halogen compounds from the ocean.
“Atmospheric chemistry involving bromine and iodine is turning out to be much more vigorous than we expected,” said CU-Boulder atmospheric chemist Rainer Volkamer, the corresponding author of the new paper published in the Proceedings of the National Academy of Sciences. “These halogen reactions can turn mercury into a form that can rain out of the air onto the ground or into oceans” up to 3.5 times faster than previously estimated, he said.
The new chemistry that Volkamer and his colleagues have uncovered, with the help of an innovative instrument developed at CU-Boulder, may also help scientists better understand a longstanding limitation of global climate models. Those models have difficulty explaining why levels of ozone, a greenhouse gas, were so low before the Industrial Revolution.
…[/font][/font]
http://www.eurekalert.org/pub_releases/2015-06/dc-rmp062915.php
[font face=Serif]Public Release: 29-Jun-2015
[font size=5] Recent mercury pollution on the rise, but quick to change, Dartmouth-led study shows[/font]
Dartmouth College
[font size=3]HANOVER, N.H. - A Dartmouth-led study using a 600-year-old ice core shows that global mercury pollution increased dramatically during the 20th century, but that mercury concentrations in the atmosphere decreased faster than previously thought beginning in the late 1970s when emissions started to decline.
…
Overall, the new study shows 78 percent of mercury pollution occurred during the 20th century, 14 percent during the Gold Rush (1850-1900), and 8 percent during the Colonial Period (1603-1850). Those figures differ significantly from emissions estimates that are used to drive global mercury models, which attribute 43 percent of mercury emissions to the 20th century, 27 percent to the Gold Rush and 30 percent to the Colonial Period. The smaller amounts of pre-20th century emissions found in this study suggest there is significantly less "legacy" mercury from early mining in the modern environment than previously thought.
Most importantly, the new study shows that mercury concentrations in the atmosphere respond more quickly to changes in emissions than most current models predict. For example, concentrations decreased quickly after the Gold Rush and after environmental legislation was enacted to reduce emissions in the 1970s. This suggests that future efforts to cut mercury emissions will have a larger impact on reducing pollution than current models predict.
"The ice core record shows clearly how efforts to reduce mercury emissions have decreased pollution in the past. But the recent rise in mercury pollution from coal burning and small-scale gold mining show that there is more work to be done," says lead author Sam Beal, a research chemist at the U.S. Army Corps of Engineers' Cold Regions Research and Engineering Laboratory who conducted this work as a Ph.D. student in Dartmouth's Department of Earth Sciences.
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[font size=5] Recent mercury pollution on the rise, but quick to change, Dartmouth-led study shows[/font]
Dartmouth College
[font size=3]HANOVER, N.H. - A Dartmouth-led study using a 600-year-old ice core shows that global mercury pollution increased dramatically during the 20th century, but that mercury concentrations in the atmosphere decreased faster than previously thought beginning in the late 1970s when emissions started to decline.
…
Overall, the new study shows 78 percent of mercury pollution occurred during the 20th century, 14 percent during the Gold Rush (1850-1900), and 8 percent during the Colonial Period (1603-1850). Those figures differ significantly from emissions estimates that are used to drive global mercury models, which attribute 43 percent of mercury emissions to the 20th century, 27 percent to the Gold Rush and 30 percent to the Colonial Period. The smaller amounts of pre-20th century emissions found in this study suggest there is significantly less "legacy" mercury from early mining in the modern environment than previously thought.
Most importantly, the new study shows that mercury concentrations in the atmosphere respond more quickly to changes in emissions than most current models predict. For example, concentrations decreased quickly after the Gold Rush and after environmental legislation was enacted to reduce emissions in the 1970s. This suggests that future efforts to cut mercury emissions will have a larger impact on reducing pollution than current models predict.
"The ice core record shows clearly how efforts to reduce mercury emissions have decreased pollution in the past. But the recent rise in mercury pollution from coal burning and small-scale gold mining show that there is more work to be done," says lead author Sam Beal, a research chemist at the U.S. Army Corps of Engineers' Cold Regions Research and Engineering Laboratory who conducted this work as a Ph.D. student in Dartmouth's Department of Earth Sciences.
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3 replies
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...over the southeastern United States. Hmmmmmm 
That could explain a lot.
