Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Atmospheric mysteries unraveling

30.06.2015

New findings may be key to explaining mercury -- and much more

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.


The Differential Optical Absorption Spectroscopy instrument hangs under the wing of a research aircraft. Relying on measurements from the instrument, CIRES Fellow Rainer Volkamer and international colleagues report that halogens, natural chemicals from the ocean, can contribute to much more vigorous atmospheric chemistry than previously understood. The discovery may help explain levels of mercury contamination in the air, on land and in the oceans, and some climate mysteries as well. More: cires.colorado.edu/news/press/halogenchem

Credit: David Oonk/CIRES

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.

"The models have been largely untested for halogen chemistry because we didn't have measurements in the tropical free troposphere before," Volkamer said. "The naturally occurring halogen chemistry can help explain that low ozone because more abundant halogens destroy ozone faster than had previously been realized."

Volkamer is a Fellow of CIRES, the Cooperative Institute for Research in Environmental Sciences, at CU-Boulder and is an associate professor in the Department of Chemistry and Biochemistry. For the new paper, he worked with scientists from the U.S., China, Denmark and England.

The international team relied on a differential optical absorption spectroscopy instruments (DOAS) that Volkamer's research group built to measure tiny amounts of atmospheric chemicals including highly reactive bromine oxide and iodine oxide radicals.

Those radicals are very short-lived in the air, and collecting air samples doesn't work well. DOAS uses solar light, measuring the scattering and absorption of sunlight by gases and particles to identify the chemicals' distinct spectroscopic fingerprints and to quantify extremely small amounts directly in the atmosphere.

Reactions involving those bromine and iodine radicals can turn airborne mercury--emitted by power plants and other sources--into a water-soluble form that can stay high in the atmosphere for a long time. High in the air, the mercury can sweep around the world.

Towering thunderstorms can then pull some of that mercury back out of the atmosphere to the ground, lakes or oceans. There, the toxin can accumulate in fish, creating a public health concern.

Volkamer's team's measurements show that the first step in that process, the oxidation of mercury in the atmosphere by bromine, happens up to 3.5 times faster than previously estimated because of halogen sources in oceans. Their work may help explain a mystery:

For many pollutants, thunderstorms can rain out the chemicals quickly, so by the end of the storm there's little left in the air. Not so for mercury. Volkamer said its concentration in rainwater remains constant throughout a storm.

"To some extent, because of these halogens, we have a larger pool of oxidized mercury up there," Volkamer said.

Naturally occurring bromine in air aloft illustrates the global interconnectedness between energy choices affecting mercury emissions in developing nations, and mercury deposition in the U.S.

Finally, the measurements will be helpful for climate modelers seeking to improve their understanding of halogen impacts on ozone and other greenhouse gases.

###

The 24 authors of "Active and widespread halogen chemistry in the tropical and subtropical free troposphere" published in the current issue of the Proceedings of the National Academy of Sciences (PNAS) are from CU-Boulder and CIRES, NOAA, Harvard University, the University of Copenhagen, the National Center for Atmospheric Research, and more. The work was funded primarily by the National Science Foundation.

CIRES is a partnership of NOAA and the University of Colorado Boulder.

Katy Human | EurekAlert!

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>