Xuhui Lee, professor of meteorology, and Jeffrey Sigler, a recent Yale Ph.D. and now a postdoctoral researcher at the University of New Hampshire, co-authored the Yale study "Recent Trends in Anthropogenic Mercury Emission in the Northeast United States." They found that between 2000 and 2002 the emission rate of mercury decreased by 50 percent, but between 2002 and 2004 the rate increased between 50 and 75 percent. During that five-year period, overall emissions declined by 20 percent.
The dramatic annual changes in mercury emissions, the study's authors say, cannot be explained climatologically by air flow patterns that would bring either clean or polluted air into the region.
Mild winters and a correspondent decrease in the need for regional power plants to burn coal could partially explain the decline in mercury emissions, according to the authors. The study, published this summer in the Journal of Geophysical Research-Atmospheres, estimates that power plants account for up to 40 percent of total emissions in New Jersey, New York and Pennsylvania and in New England.
"The study highlights just how important power plants are in influencing regional mercury emission," said Sigler. "We should not forget other source categories when formulating abatement policies, since they also contribute significant amounts to the total emissions," Lee added.
Mercury, which converts to highly toxic methyl mercury in ground water, is found in fish and can cause neurological problems in developing fetuses and dementia and organ failure in adults who eat fish in large amounts and over long periods.
The Yale study was conducted at Great Mountain Forest in northwestern Connecticut. The measurements were restricted to wintertime so data on carbon dioxide that comes from the same combustion sources as mercury would not be distorted by photosynthesis. The researchers used carbon dioxide to trace mercury back to its sources with a unique method called "tracer analysis."
"To our knowledge, using the carbon dioxide to trace mercury over a long time period hasn't been done before," said the authors. "We started with actual mercury that's in the atmosphere, worked back to sources that emit it, then calculated the emission rate."
The U.S. Environmental Protection Agency, which does not regulate mercury emissions, determines the mercury emission rate by taking an inventory of existing sources. "Although the EPA's approach is highly useful, it requires accurate measurements of mercury emitted from the smokestack per ton of fuel burned," said Sigler. "These data are hard to come by. Our top-down technique circumvents those rather cumbersome problems and allows for much more timely estimates of mercury emission. It's difficult to get annual changes in the emission rate with the inventory approach."
Janet Rettig Emanuel | EurekAlert!
Climate satellite: Tracking methane with robust laser technology
22.06.2017 | Fraunhofer-Gesellschaft
How reliable are shells as climate archives?
21.06.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
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13.06.2017 | Event News
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23.06.2017 | Physics and Astronomy
23.06.2017 | Information Technology