From the Georgia Institute of Technology
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.
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
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High levels of molecular chlorine in the Arctic atmosphere
Liao et al, Nature Geoscience (2014) doi:10.1038/ngeo2046
Abstract
Chlorine radicals can function as a strong atmospheric oxidant1, 2, 3, particularly in polar regions, where levels of hydroxyl radicals are low. In the atmosphere, chlorine radicals expedite the degradation of methane4, 5, 6 and tropospheric ozone4, 7, and the oxidation of mercury to more toxic forms3. Here we present direct measurements of molecular chlorine levels in the Arctic marine boundary layer in Barrow, Alaska, collected in the spring of 2009 over a six-week period using chemical ionization mass spectrometry. We report high levels of molecular chlorine, of up to 400 pptv. 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 are required for molecular chlorine formation. Using a time-dependent box model, we estimate that the chlorine radicals produced from the photolysis of molecular chlorine oxidized more methane than hydroxyl radicals, on average, and enhanced the abundance of short-lived peroxy radicals. Elevated hydroperoxyl radical levels, in turn, promoted the formation of hypobromous acid, which catalyses mercury oxidation and the breakdown of tropospheric ozone. We therefore suggest that molecular chlorine exerts a significant effect on the atmospheric chemistry of the Arctic.
[snip – your commentary on “malicious” reading is too stupid to allow -mod]
Natural mining (glaciation) is you biggest source of mercury. When you grind rock you get lots of heavy metals.
Meanwhile in the Antarctic:
“We have just pulled up the anchor and are sailing out of Newcomb Bay having completed the Casey Resupply. We had 5 barge trips of cargo to come on board to load the final RTA cargo. Loaded the Navy boat and barge on board and prepared for sea. We departed at 1.05pm with everyone happy to be on our way. I wish to thank the crew of the Aurora Australis, the Casey Station Leader, the Casey shore based crews and the expeditioners on station and on board for making this a successful resupply. As mentioned in previous sitreps it takes a large number of people working in synch with each to make a resupply happen safely and successfully. Tonight we are all looking forward to a barbecue on the trawl deck. To have a bbq whilst sailing past icebergs is a unique and quite surreal experience. Cheers Leanne and Mark”
No Hobart ETA yet.
if its the first time measured there how do they know its not normal ?
and 400 per 1,000,000,000,000……wow. I am so worried…
Ferdinand Engelbeen says:
January 15, 2014 at 2:10 am
http://wattsupwiththat.com/2014/01/15/high-levels-of-molecular-chlorine-found-in-arctic-atmosphere/#comment-1536483
Great stuff! We can put this paper to bed I see.
Clarification:
As per melting sea ice.
Ferdinand, an excellent synopsis. May I suggest that you write a letter of rebuttal to Nature Geoscience on this? See: http://www.nature.com/ngeo/authors/index.html
Jimbo: “”Cl varies from <0.02 to 4 ?g Cl/m3STP in the filter samples""
Any idea what "in the filter samples" means?
If "?g" is nanograms, then my calculator says (4 x 10^-9) / (1.2 x 10 ^ 3) * 29 / 71 = 1.4 x 10^-12, i.e., 1.4 parts per trillion, more than two orders of magnitude less than the 400 parts per trillion reported by the paper to which the top post is directed.
Michael says:
January 15, 2014 at 12:22 am
How did this pass peer-review when the abstract mixes the terms chlorine radicals and molecular chlorine? I assume they mean atomic chlorine when they they chlorine radicals which is more reactive Molecular chlorine away from water is pretty chemically stable. Metals don’t react with it. I doubt organic material would either at any appreciable rate.
Chlorine atoms are chlorine radicals. When you photolyze a chlorine molecule you get two neutral chlorine atoms which, because they each have an unpaied elecron, are radicals.
Of some relevance to the mercury discussion may be Mr. Eschenbach’s posts here and here.
@- richardscourtney
“It does not follow that the background level of mercury must be at least half from human activities EVERYWHERE ….If you had a rational argument to refute Ferdinand then you would have provided it and not the nonsense you have.
I provide this link to Ferdinand’s fine post help those who missed it”
If you had read the comment you link to carefully you would have seen that Ferdinand was discussing chlorine NOT mercury.
In re Millipore filters, are commonly used to measure insoluble (metal) content by filtering aliquot and weighing provides mass/mass fraction. In later practice, visual density comparison suffices for maintenance. So it depends on the sampled and filtered volume.
Yeah, Right.
Are these folks complete idiots? Or do they just think we are?
There are VOLCANOES, active volcanoes up there. October 10, 2013 Kliuchevskoi eruption continues – column of ash up to 5.3 km, Kamchatka
There are even active volcanoes under the sea. Arctic Volcanoes Found Active at Unprecedented Depths
The chart in the article shows SO2 as number 3 after H2O and CO2, as much as 11% of the gases depending on the volcano. HCl can be as much as 3%.
Also see blog article: Volcanoes Belch Chlorine
A thanks to Dr. Art Robinson who mentioned Cl and volcanoes and ozone holes many many years ago when the taking of samples was done down wind of an active volcano and mankind was blamed for the pollution and ozone hole. The lying in politicized science has been going on for years.
izen:
At January 15, 2014 at 6:12 am you say to me
And if your brain were made of dynamite it would not be sufficient to blow your hat off. So what?
Richard
Katherine says: @ur momisugly January 15, 2014 at 1:33 am
Yeah? How can they be so sure of that? What’s their basis for this claim? How about all the naturally burning coal seams?
>>>>>>>>>>>>>
Not to mention from the land. Cinnabar is a mercury containing rock (ore) that has been mined for ~5000 or more years. Erosion of the rock puts the mercury into the sea.
Also see WUWT: Mercury, the Trickster God by Willis.
Ferdinand Engelbeen says:
Did you mean Chlorine – VCM – PVC? with a butadiene inhibitor for bulk shipment of the VCM?
I thought ice has no salt in it, so how could salt/chlorine be released from MELTING ice?
I see from the photo at the press release that at least one of the instruments used by these researchers was attached directly to plywood. Any chance that part of their chlorine measurement resulted from emissions from the plywood?
izen says: @ur momisugly January 15, 2014 at 3:25 am
….Given that at least half of the background mercury levels we measure are human made…
>>>>>>>>>>>>>
Izen humans don’t MAKE elements unless you are talking nuclear reactions. Like every other living thing we concentrate the elements/ molecules that are useful to us. We are just a heck of a lot more inventive compared to fungi or termites.
As far as mercury in the sea goes, humans have little to do with it and geological processes a great deal. For example the Arbuckle Mountains were a high mountain range, that have been severely leveled as a result of millions of years of erosion. The Arbuckle Mountains were originally as tall as the Himalayas. At the time they formed, the Appalachians were much higher than they are today — more like the present-day Rocky Mountains. While the Atlantic Ocean was still in its infancy, the Appalachians were already being attacked by erosion. For the last 100 million years, erosion has carved away the mountains, leaving only their cores standing.
Purely out of idle curiosity :
Assuming we can trust the measurements at least, and argue about the rest of the paper later, doesn’t this imply that the CFC ban was a waste of time?
Assuming that the Chlorine must be released from deposited salt. There can’t be many processes that deploy the energy needed to break the ionic bond in an NaCL molecule.Direct solar exposure or radiation absorption? Otherwise you’d have to look for a biochemical enzyme driven process surely?
Dodgy Geezer says:
January 15, 2014 at 4:18 am
Er…. does this mean that we can have our cheap, safe CFCs back now…?
Thought not….
>>>>>>>>>>>>
A patent is good for 17 years and can be renewed once so that is 34 years. The Montreal Protocol went into force on January 1st, 1989. 34 years later is 2023…..
SEE: BUSINESS STRATEGY AND THE ENVIRONMENT, VOL. 6, 276±286 (1997)
THERE’S MONEY IN THE AIR: THE CFC BAN AND DUPONT’S
REGULATORY STRATEGY
@- Gail Combs
“Izen humans don’t MAKE elements unless you are talking nuclear reactions. Like every other living thing we concentrate the elements/ molecules that are useful to us. We are just a heck of a lot more inventive compared to fungi or termites.”
Fair point, we extract and concentrate elements and molecules in far greater quantities and faster than natural processes.
@-“As far as mercury in the sea goes, humans have little to do with it and geological processes a great deal. ”
No, historical data on mercury levels preserved in human and animal hard tissues shows clearly that the natural background level was far below present levels until around the 1850s. Then industrial extraction massively increased the environmental levels with the elemental mercury we emit spreading worldwide, its conversion to soluble divalent mercury causes it to end up in the oceans where it is concentrated into the food chain. Pre-industrial samples do not show anything like the present day levels of mercury contaminattion of the seas or the food chain.
@- Mike Ozanne
Purely out of idle curiosity :
Assuming we can trust the measurements at least, and argue about the rest of the paper later, doesn’t this imply that the CFC ban was a waste of time?
No, this chlorine is too reactive and water soluble to make it to the stratosphere where ozone depletion takes place.
NASA confirmed some time ago that the chlorine that depletes ozone in the stratosphere comes from human CFCs by direct sampling with an old U2 spy plane.
And the isotope fingerprint proves it is anthropogenic.
Joe Born says:,
The top post says
Aren’t orders of magnitude then irrelevant?
I love the way IZEN makes the science sound so… well… settled. GK