From the University of Bristol
The compound, carbon tetrachloride, contributes to the destruction of the Earth’s ozone layer, which protects us from harmful ultraviolet radiation.
As a result, the production of carbon tetrachloride has been banned throughout the world since 2010 for uses that will result in its release to the atmosphere. However, recent studies have shown that global emissions have not declined as expected, with about 40,000 tonnes still being emitted each year.
The origin of these emissions has puzzled researchers for many years.
Alongside collaborators from South Korea, Switzerland, Australia and the USA, researchers at the University of Bristol aimed to quantify emissions from eastern Asia.
To do this, they used ground-based and airborne atmospheric concentration data from near the Korean peninsula and two models that simulate the transport of gases through the atmosphere.
Their results, published in the journal Geophysical Research Letters, show that around half of the ‘missing’ global emissions of carbon tetrachloride originated from eastern China between 2009 and 2016.
Lead author, Dr Mark Lunt, from the University of Bristol’s School of Chemistry, said: “Our results show that emissions of carbon tetrachloride from the eastern Asia region account for a large proportion of global emissions and are significantly larger than some previous studies have suggested.
“Not only that, but despite the phase out of carbon tetrachloride production for emissive use in 2010, we found no evidence for a subsequent decrease in emissions.”
In fact, emissions from certain regions may have increased slightly since 2010. The results from the study show the emergence of a new source of emissions from the Shandong province of China after 2012.
Whilst the results of this and earlier studies in Europe and the USA now explain a large part of the global distribution of carbon tetrachloride emissions, there are still large gaps in our knowledge. Furthermore, recent reports have suggested that very large amounts of this gas may be emitted inadvertently during the production of other chemicals such as chlorine.
Dr Matt Rigby, Reader in Atmospheric Chemistry at the University of Bristol and co-author, said: “Our work shows the location of carbon tetrachloride emissions. However, we don’t yet know the processes or industries that are responsible. This is important because we don’t know if it is being produced intentionally or inadvertently.”
He also added: “There are areas of the world such as India, South America and other parts of Asia, where emissions of ozone-depleting gases may be ongoing, but detailed atmospheric measurements are lacking.”
It is hoped that this work can now be used by scientists and regulators to identify the cause of these emissions from eastern Asia. Ultimately, if these emissions can be avoided, it would hasten the recovery of the stratospheric ozone layer.
Dr Lunt said: “Studies such as this show the importance of continued monitoring of ozone-depleting gases. There is a temptation to see ozone depletion as a problem that has been solved. But the monitoring of man-made ozone-depleting gases in the atmosphere is essential to ensure the continued success of the phase-out of these compounds.”
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Continued Emissions of the Ozone‐Depleting Substance Carbon Tetrachloride From Eastern Asia
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL079500
Abstract
Carbon tetrachloride (CCl4) is an ozone‐depleting substance, accounting for about 10% of the chlorine in the troposphere. Under the terms of the Montreal Protocol, its production for dispersive uses was banned from 2010. In this work we show that, despite the controls on production being introduced, CCl4 emissions from the eastern part of China did not decline between 2009 and 2016. This finding is in contrast to a recent bottom‐up estimate, which predicted a significant decrease in emissions after the introduction of production controls. We find eastern Asian emissions of CCl4 to be 16 (9–24) Gg/year on average between 2009 and 2016, with the primary source regions being in eastern China. The spatial distribution of emissions that we derive suggests that the source distribution of CCl4 in China changed during the 8‐year study period, indicating a new source or sources of emissions from China’s Shandong province after 2012.
Plain Language Summary
Carbon tetrachloride is one of several man‐made gases that contribute to the depletion of the ozone layer high in the atmosphere. Because of this, restrictions were introduced on the use of this ozone‐depleting substance, with the expectation that production should by now be close to 0. However, the slower than expected rate of decline of carbon tetrachloride in the atmosphere shows this is not the case, and a large portion of global emissions are unaccounted for. In this study we use atmospheric measurements of carbon tetrachloride from a site in East Asia to identify the magnitude and location of emissions from this region between 2009 and 2016. We find that there are significant ongoing emissions from eastern China and that these account for a large part of the missing emissions from global estimates. The presence of continued sources of this important ozone‐depleting substance indicates that more could be done to speed up the recovery of the ozone layer.
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China is ignoring UN and enviro-Mentalists diktats?
I’m shocked…. Shocked, I tell you! /s
It’s in the Five Year Plan of Dear Leaders.
30°20’01.36″ N 120°18’25.30″ E
Seems to be that region I found in Google Earth
“we don’t know if it is being produced intentionally or inadvertently” Already lined up for an excuse before the investigation so China will get another pass at destroying the environment. But it’s all a conspiracy theory….. isn’t it?
Errrrrr, hello Bristol.
It was a joke. By DuPont
They set up a huuuuuge party in Montreal where everyone could get stupid and have a good time.
Nothing intrinsically wrong with that but in the midst of all the fun, DuPont dropped A Stinker – a massive and blatant scientific-sounding porky-pie. Concerning ozone and a refrigerant gas that they manufactured and that was going to go ‘out of patent’ in the near future.
And nobody had the brains, the guts or where-with-all to stand up and say “Sorry, I don’t get it”
Nobody.
Net result now is that every refrigeration device now made has about 50% of the efficiency of devices made prior to the Montreal Party.
How many years later and you, Bristol, still haven’t got it.
Suggest you try thinking for yourselves and NOT relying on what NASA says.
And my today adventure took me to a tyre depot. Hooda thunk I’d find ozone there but I did.
2 little metal bottles, like camping gas (Propane or Butane) but a blue/green colour.
The Small Print on a small label told us “12kg of R134a”
Lovely, for fixing air-cons.
But the Large Print, on an unmissable, self-important& huuuge white sticky-on label told us that these bottles contained:
“A Greenhouse Gas controlled and authorised by the Kyoto Protocol”
Kyoto?
Refrigerators mostly use isobutane in Europe and are always bursting into flames. That’s what started the Grenfell tower fire. The cladding probably released some CFCs and HFCs.
Yep, thanks for pointing that out. That kind of thing is the insanity that you get when you pretend that the existence of the human race and all life of Earth depends on something being done. Priorities get turned upside down and some very stupid and unnecessary things are deemed “necessary”.
We have the eco-warriors to thanks for that catastrophe.
“The results show that the source of carbon tetrachloride is located in the northeast near a chemical plant in the study area, whose pollutant concentration is diminishing from northeast to southwest. The main reasons to the pollution are that factories discharge waste water at random, leakage of open channel and culvert, sewage
irrigation and the vulnerability of geological conditions in this area.”
http://iopscience.iop.org/article/10.1088/1755-1315/82/1/012058/pdf
Glenn,
Good find! Seems quite simple to find the main source(s), but remains if the industry there (or even the government) want to do anything on that…
Hummmm, that looks pretty close to those massive Apple product factories.
One sentence in that report I don’t think can be right:
Furthermore, recent reports have suggested that very large amounts of this gas may be emitted inadvertently during the production of other chemicals such as chlorine.
Chlorine is produced by the electrolysis of a salt solution (mostly NaCl, sometimes KCl), there is no carbon source present to form CCl4, so that is not directly possible…
It may be formed by the chlorination of other compounds, of which vinyl chloride monomer (for PVC) is the largest industrial production, but that is not directly from chlorine manufacturing…
Carbon tetrachloride is used in the process to refine Uranium (see wikipedia)
I doubt that’s it’s only use. It’s also likely a byproduct of some other process. Chemistry is funny that way.
This man made chem is 10% of chlorides in the troposphere that deplete ozone? I seriously doubt that! this is just like the freon scam:
https://www.youtube.com/watch?v=tc2M_FKyvaE
chlorine is blasted out of volcanoes all the time and it depletes ozone, then the sun just manufactures more ozone .. all of this stuff is a scam, the amount of chlorides humans put into the atmosphere is nothing and these hevy molecules are less liky to go up that high.
@Bill Marsh
October 29, 2018 at 10:02 am
“Fairly soon almost everything a Chinese citizen does/says and who says what in their presence will be recorded and monitored and a ‘social grade’ will be assigned. That grade affects your job, travel, cost of goods, stores you may go to, educational opportunities, etc”
It’s already in place:
https://twitter.com/Psythor/status/1056811593177227264
This is a perfect opportunity to study where the carbon tet goes, and what happens to it. We have a known source near sea level. Take samples via plane and balloon to track it. The weather models for wind can give a good direction to start with. We could use this for some real science, including determining how much carbon tet gets into the stratosphere, and can we see a depletion of the ozone above the plume, etc.
Actually this is the opposite of what they did to locate the source, they made measurements at various locations and used weather model to trace it back to the origin.