Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

High Levels of Molecular Chlorine Found in Arctic Atmosphere

14.01.2014
Scientists studying the atmosphere above Barrow, Alaska, have discovered unprecedented levels of molecular chlorine in the air, a new study reports.

Molecular chlorine, from sea salt released by melting sea ice, reacts with sunlight to produce chlorine atoms. These chlorine atoms are highly reactive and can oxidize many constituents of the atmosphere including methane and elemental mercury, as well activate bromine chemistry, which is an even stronger oxidant of elemental mercury. Oxidized mercury is more reactive and can be deposited to the Arctic ecosystem.


Greg Huey

Jin Liao checks the instrumentation in Barrow, Alaska, during a research trip to measure molecular chlorine in the atmosphere. Liao is the first author of the study, published January 12, 2014, in the Advance Online Publication of Nature Geoscience

The study is the first time that molecular chlorine has been measured in the Arctic, and the first time that scientists have documented such high levels of molecular chlorine in the atmosphere.

“No one expected there to be this level of chlorine in Barrow or in polar regions,” said Greg Huey, a professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology in Atlanta.

The study was published January 12 in the journal Nature Geoscience and was supported by the National Science Foundation (NSF), part of the international multidisciplinary OASIS program.

The researchers directly measured molecular chlorine levels in the Arctic in the spring of 2009 over a six-week period using chemical ionization mass spectrometry. At first the scientists were skeptical of their data, so they spent several years running other experiments to ensure their findings were accurate.

The level of molecular chlorine above Barrow was measured as high as 400 parts per trillion, which is a high concentration considering that chlorine atoms are short –lived in the atmosphere because they are strong oxidants and are highly reactive with other atmospheric chemicals.

Molecular chlorine concentrations peaked in the early morning and late afternoon, and fell to near-zero levels at night. Average daytime molecular chlorine levels were correlated with ozone concentrations, suggesting that sunlight and ozone may be required for molecular chlorine formation.

Previous Arctic studies have documented high levels of oxidized mercury in Barrow and other polar regions. The major source of elemental mercury in the Arctic regions is coal-burning plants around the world. In the spring in Barrow, ozone and elemental mercury are often depleted from the atmosphere when halogens — chlorine and bromine — are released into the air from melting sea ice.

“Molecular chlorine is so reactive that it’s going to have a very strong influence on atmospheric chemistry,” Huey said.

Chlorine atoms are the dominant oxidant in Barrow, the study found. The area is part of a region with otherwise low levels of oxidants in the atmosphere, due to the lack of water vapor and ozone, which are the major precursors to making oxidants in many urban areas.

In Barrow, snow-covered ice pack extends in every directly except inland. The ultimate source of the molecular chlorine is the sodium chloride in sea salt, Huey said, most likely from the snow-covered ice pack. How the sea salt is transformed into molecular chlorine is unknown.

“We don’t really know the mechanism. It’s a mystery to us right now,” Huey said. “But the sea ice is changing dramatically, so we’re in a time where we have absolutely no predictive power over what’s going to happen to this chemistry. We’re really in the dark about the chlorine.”

Scientists do know that sea ice is rapidly changing, Huey said. The sea ice that lasts from one winter to the next winter is decreasing. This has created a larger area of melted ice, and more ice that comes and goes with the seasons. This seasonal variation in ice could release more molecular chlorine into the atmosphere.

“There is definite climate change happening in the Arctic,” Huey said. “That’s changing the nature of the ice, changing the volume of the ice, changing the surface area and changing the chemistry of the ice.”

Brett Israel | Newswise
Further information:
http://www.gatech.edu

Further reports about: Arctic Ocean Molecular Target atmosphere chlorine chlorine atom polar region sea ice

More articles from Earth Sciences:

nachricht NASA covers Super Typhoon Maysak's rainfall, winds, clouds, eye
01.04.2015 | NASA/Goddard Space Flight Center

nachricht Typhoons rain away wrath
01.04.2015 | Okinawa Institute of Science and Technology (OIST) Graduate University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Lizard activity levels can help scientists predict environmental change

Research study provides new tools to assess warming temperatures

Spring is here and ectotherms, or animals dependent on external sources to raise their body temperature, are becoming more active. Recent studies have shown...

Im Focus: Hannover Messe 2015: Saving energy with smart façades

Glass-fronted office buildings are some of the biggest energy consumers, and regulating their temperature is a big job. Now a façade element developed by Fraunhofer researchers and designers for glass fronts is to reduce energy consumption by harnessing solar thermal energy. A demonstrator version will be on display at Hannover Messe.

In Germany, buildings account for almost 40 percent of all energy usage. Heating, cooling and ventilating homes, offices and public spaces is expensive – and...

Im Focus: Nonoxide ceramics open up new perspectives for the chemical and plant engineering

Outstanding chemical, thermal and tribological properties predestine silicon carbide for the production of ceramic components of high volume. A novel method now overcomes the procedural and technical limitations of conventional design methods for the production of components with large differences in wall thickness and demanding undercuts.

Extremely hard as diamond, shrinking-free manufacturing, resistance to chemicals, wear and temperatures up to 1300 °C: Silicon carbide (SiSiC) bundles all...

Im Focus: Experiment Provides the Best Look Yet at 'Warm Dense Matter' at Cores of Giant Planets

In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as...

Im Focus: Energy-autonomous and wireless monitoring protects marine gearboxes

The IPH presents a solution at HANNOVER MESSE 2015 to make ship traffic more reliable while decreasing the maintenance costs at the same time. In cooperation with project partners, the research institute from Hannover, Germany, has developed a sensor system which continuously monitors the condition of the marine gearbox, thus preventing breakdowns. Special feature: the monitoring system works wirelessly and energy-autonomously. The required electrical power is generated where it is needed – directly at the sensor.

As well as cars need to be certified regularly (in Germany by the TÜV – Technical Inspection Association), ships need to be inspected – if the powertrain stops...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

World Conference On Regenerative Medicine 2015: Registration And Abstract Submission Now Open

25.03.2015 | Event News

University presidents from all over the world meet in Hamburg

19.03.2015 | Event News

10. CeBiTec Symposium zum Big Data-Problem

17.03.2015 | Event News

 
Latest News

NASA covers Super Typhoon Maysak's rainfall, winds, clouds, eye

01.04.2015 | Earth Sciences

Quantum teleportation on a chip

01.04.2015 | Information Technology

Galaxy Clusters Formed as 'Fireworks'

01.04.2015 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>