back to article Carbon tetrachloride releases still too high, says NASA

Somewhere, a dry cleaner didn't get the memo: someone is putting an awful lot of carbon tetrachloride into the atmosphere, and NASA would like them to stop. Back in 1987, the compound was one of many ozone-depleting chemicals regulated under the Montreal Protocol. However, NASA said on Wednesday there's still too much of the …

  1. Anonymous Coward
    Anonymous Coward

    hooray for carbon capture

    At least now we have a better grasp (or not) of what happened when you try to capture carbon.

    maybe.

    1. Matt 21

      Re: hooray for carbon capture

      Not sure about that.

      What stands out to me is that at the time we were told these emissions had to stop or we would quickly be in a lot of trouble. Now it turns out that these emissions, while lower, are still fairly high and the predicted catastrophe hasn't happened.

      Now, I'm not saying that we shouldn't have worked to reduce CO4 but we were given false information about what would happen if we didn't. The case for stopping was exaggerated and the problem with that is that it makes people less likely to believe calls to stop other activity even if this time it's true.

      1. Tannin

        Re: hooray for carbon capture

        You could try reading the article. If you did, you would discover that the worldwide release of ozone-depleting chemicals is way, way down on historical levels, and that this particular one (amongst many) is also well down, but not as far down as hoped and expected, hence the mystery.

        You might also be interested to learn that the atmosphere scientists got it dead right: there was a hole in the ozone layer, it did (and still does) cause significant harm to (among other things) human health because of massively increased skin cancer rates - this is very serious business in the southern hemisphere and it would be vastly more serious if it wasn't for the huge public health campaigns which have led to a profound change in the way we expose ourselves to UV. 50 years ago, practically no-one wore a hat on the beach, sunblock cream was largely only used by girls and even them not much (everybody used to go dark brown all over every summer), and no outdoor worksite would have dreamed of treating sunblock cream and protective clothing as essential health and safety equipment to be issued to everyone as routin.

        Thankfully, the cooperative worldwide controls on ozone-depleting chemicals have been largely successful and we are starting to see the ozone layer gradually recover.

        You can read more at http://www.environment.gov.au/protection/ozone/ozone-science/ozone-layer

      2. Alan Brown Silver badge

        Re: hooray for carbon capture

        "Now it turns out that these emissions, while lower, are still fairly high and the predicted catastrophe hasn't happened."

        CCl4 emissions may be higher than they should be, but CFC emissions overall are WAY down, as the article noted.

        CFCs take about 60 years to percolate to the stratosphere, so it will take some time before the ozone hole goes away. It continued to enlarge for several years after limiting treaties were signed and has only recently shown any signs of shrinkage.

        BTW, general chlorine releases in the troposphere aren't an issue. these chemically bind very quickly. The issue with CFCs is that they are extremely stable and they act as a catalyst to vastly speedup the breakdown of O3 (which is inherently unstable anyway) to O2 at a rate exceeding 1000:1 before ultraviolet light breaks the molecules down and the chlorine atoms are able to bind with something else and rise further up or sink back down.

  2. razorfishsl

    Still used in many production facilities in China for cleaning PCB's

    1. Alan Brown Silver badge

      "Still used in many production facilities in China for cleaning PCB's"

      China's limits for CFCs are fairly high, but environmental awareness is relatively high and minimising losses makes economic sense anyway.

      Still, when I was using it to clean boards and other stuff 30 years ago there was no indication that it was a ozone depleter, just warnings that it's a nasty chemical which can trash your liver if you get too much on your skin.

      1. Anonymous C0ward
        Pint

        Chemicals that trash your liver

        In for a penny, in for a pound. -->

  3. SoltanGris
    Coat

    KHAAAAAAAAAN

    Because George Bush.

    Of course.

    http://youtu.be/wRnSnfiUI54?t=16s

  4. Richard Boyce
    Unhappy

    Sensors

    So put some sensors aboard normal commercial aircraft, map the concentrations, and publish the maps. There need be no mystery about where the CCl4 is being released in any sustained way. This isn't a science problem, it's first and foremost a political problem.

    1. Hugh Pumphrey

      Re: Sensors

      "So put some sensors aboard normal commercial aircraft, map the concentrations, and publish the maps. "

      The problem with many of these Cl-bearing compounds is that down here in the troposphere they are essentially indestructible and hence become very evenly mixed. These molecules are not like farts: if you can smell farts, someone near you is farting and you can probably find out who by following the smellyness gradient upwards. And the entire planet doesn't smell of fart because the molecules get destroyed and rained out of the atmosphere quickly. Ozone-depleting molecules, OTOH, are emitted in tiny amounts but do not get destroyed until the air reaches the stratosphere. So if you measure them down here you tend to get the same answer nearly anywhere, unless you are right next to a leaking factory (in which case you probably knew where the CCl4 was coming from already).

      1. Anonymous Coward
        Anonymous Coward

        Re: Sensors

        It's probably China though.

  5. drexciya

    Odd, I thought that CCl4 was pretty much off-limits in the industry because is it is very carcinogenic. I do remember a chemistry professor mourning that he couldn't use it anymore as a solvent for reactions involving radicals, which it is very well suited for.

    I didn't know that it is bad for the ozone layer as well. If Chinese companies use it on a large scale for whatever reason, I'd really not like to be anywhere near them.

    1. Nigel 11

      Ozone-eaters

      Any halogenated volatile compound is a potential ozone-eater. The more stable it is under ordinary ground-level atmospheric conditions, the worse it is. The mechanism is that the molecules slowly diffuse up into the ozone layer, where solar UV radiationbreaks them down. This releases halogen ions, which then catalyze the destruction of ozone. If they break down at a significant rate in the lower levels of the atmosphere, they are washed out of the lower atmosphere before they can contribute to ozone depletion.

  6. Duncan Macdonald

    Dry Cleaning ?

    Carbon tetrachloride used to be used as a dry cleaning solvent. It would not surprise me to find it still being used in some of the less well regulated countries.

    1. Richard Jones 1
      Holmes

      Re: Dry Cleaning ?

      Very unlikely to be from dry cleaning now. Dry cleaning is a lossy process hence you could smell the product in the long gone past. Unless someone is making and spitting new stuff into the cleaning business the old stocks should have been lost by now. If levels are increasing someone or something is making it or slowly releasing their strategic stocks. It is a long time since tetrachloride was a favoured production chemical in any business due to its 'side effects'. In the UK and I suspect most places Perchloretheylene came in to replace it industrially during the 1960s, so either someone is very keen to use it for their favourite military project, a clandestine maker has forgotten to stop making it and is venting excess production or it is a side stream output from an old or current activity. Due to its relative stability, it could possibly be that very old stock is simply leaching out and that with further time the rate will decline until it becomes negative.

      However, the watchers of these things hate doubt so it is wise to check that no one is breaking the rules or that some other unknown process, natural or industrial is creating more of the stuff. The latter case would be the more worrying.

  7. roger stillick
    Facepalm

    Carbon Tet ?? banned since the 1950's... I thought...

    WIKI=dry cleaning | Wiki= carbon Tet, then look at Safety of carbon Tet...

    Seems that since 2008 the home laundry industry had sucessfully weaned the home laundry users off high phosperous detergents that promote algy growth in streams, lakes,and rivers...yea, Green Solution...the replacement is low e soaps, which don't clean too well and seem to need a bleach added to kill germs, clean clothes and not leave a bad smell in the washing machine...

    Unfortunately, home laundry Low-e soaps used with chlorine bleach CAUSE HI-LEVELS of poisonous Carbon Tet to be generated (thats why the clothes get cleaned, used to be called 'dry cleaning')...

    IMHO= my water saving, Low-e soap using, enviromentally safe, sweet smelling, front loading washing machine was known since 2008 to be an enviromental hazard of toxic, ozone layer killing proportions when used w/ chlorine bleach... which, by the way, got a "lemon smell' added to mask the Carbon tet odor ( I actually thought that smell was 'Oxygen Bleach' smell= it wasn't bad / just banned since 1970 for any home use)...

    The hippies are right= don't wash your clothes !! just hang them out in the rain n air dry... or boil them w/lye soap n air dry...bathe monthly, Use no.4711 Cologne...at least you get no algee filled waterways or depleted ozone layers...RS.

    1. Pascal Monett Silver badge

      Interesting post.

      I was going to blame the cows, but blaming clean people is a novel approach.

      1. wdmot

        Those cleaning people

        @Pascal

        From that link, carbon tetrachloride "is mainly produced from methane":

        CH4 + 4 Cl2 → CCl4 + 4 HCl

        So if I understand that correctly... using chlorine bleach to clean dairy equipment near farting cows produces CCl4?

    2. Richard Jones 1
      Unhappy

      Re: Carbon Tet ?? banned since the 1950's... I thought...

      I thought most people used the so called OXY bleaches for laundry to avoid or mitigate the effects on colours? I certainly agree on the odour from too many environmentally sound 'cleaning machines.' A weekly boil wash of the towels along with the odd oxy wash does help with that issue.

      Thank you for suggesting, or perhaps pointing out a possible new source. It appears the only law the lobby industry cannot repeal is the law of unintended consequences.

    3. Vic

      Re: Carbon Tet ?? banned since the 1950's... I thought...

      It certainly wasn't banned universally since the 1950s.

      We were still using it as switch cleaner in the late '70s / early '80s.

      Vic.

    4. Peter Simpson 1
      Holmes

      Re: Carbon Tet ?? banned since the 1950's... I thought...

      Unfortunately, home laundry Low-e soaps used with chlorine bleach CAUSE HI-LEVELS of poisonous Carbon Tet to be generated (thats why the clothes get cleaned, used to be called 'dry cleaning')...

      The paper:

      http://pubs.acs.org/doi/abs/10.1021/es702355u

    5. roger stillick
      Facepalm

      Re: Carbon Tet ?? banned since the 1950's... I thought...Pt.2

      So after 2 months of not using chlorine bleach in my front loader, all my clothes faintly smell like dirty gym towells, or 'Back to the Bleach' ( carbon-tet generated cleaning)... they win, i give up, i need clean smelling clothes as my friends are starting to ask if i'm ok... i'm not= no clean clothes...RS.

  8. JimmyPage Silver badge
    Headmaster

    Pedant alert

    ISTR the proper name is now tetrachloromethane. Certainly was when I did chemistry (A level) back in 1984.

    Also used in fire extinguishers IIRC.

    1. Nigel 11

      Re: Pedant alert

      Carbon Tetrachloride is no less proper. It's as clear and unambiguous as tetrachloromethane - there is only one possible way to assemble one carbon and four chlorine atoms. It's when you get to more complex molecules that something like "pentane" becomes ambiguous. Do you mean n-pentane, or 2-methybutane (aka isopentane)? As the molecule gets bigger still there is a combinatorial explosion. "Proper" chemical names give an unambiguous description of a molecule, but not necessarily a unique one. You can describe a large molecule in many ways, depending on which group of atoms you start with. (There are various conventions, that work up to a point ...). Also if you are buying a solvent rather than a feedstock, you don't care if it's a mixture of similar molecules just as long as none of the things in the mixture is unduly toxic or prone to interfering with whatever reactions the dissolved substances are undergoing.

      Carbon Tet hasn't been used for fire extinguishers for a long time. When it was (1930s?), leaks and accidental discharges could be deadly. Inhaling Carbon Tetrachloride while your liver is processing lots of ethyl alcohol is seriously bad news.

  9. dncnvncd

    knowing what you don't know

    The most important takeaway is that this scientist admitted there was an unknown source or process. Chlorinated hydrocarbons are nasty things, but considering the natural leakage of hydrocarbons on the ocean floor and the amount of chlorine in the ocean, Nature might have a some chemical surprises of it's own.

    1. Nigel 11

      Re: knowing what you don't know

      Ocean life produces small amounts of methyl chloride, larger amounts of methyl bromide, and huge amounts of methyl iodide. Also amounts of other halogenated hydrocarbons small compared to human production. Natural emissions of methyl iodide outweigh human emissions by at least one order of magnitude. (It's a major component of the "smell of the sea" that you can detect a few miles inland with a breeze from that direction).

      Fortunately, methyl iodide has a shortish half-life in the ground-level atmosphere, because iodine would otherwise be a far more potent destroyer of ozone than chlorine.

      Methyl iodide is an extremely potent greenhouse gas as well as an ozone eater. It's long been an evolutionary puzzle as to what it was that kept the Earth from freezing, back when the sun was young (so considerably cooler than today) and when the atmosphere did not contain oxygen. Methane and CO2 aren't thought to be sufficiently potent greenhouse gases for back then. My theory is lots of methyl iodide, stable in a reducing (methane, nitrogen, CO2) atmosphere. It's created by cyanobacteria in today's oceans, and they are amongst the most ancient and radiation-tolerant of life-forms, so why not the same back then? When they'd finally emitted enough photosynthetic oxygen to convert all the planet's near-surface Iron-II into Iron-III, the oxygen built up in the atmosphere, the methyl iodide levels dropped to today's low level, and (not coincidentally?) the "snowball earth" episode occurred. Which in turn seems to have driven the emergence of higher life-forms. But maybe that's the unlikely event, and a possible answer to the Fermi paradox - most other places, simple life drives itself to extinction when it finally converts its atmosphere to oxygen?

  10. Anonymous Coward
    Anonymous Coward

    Ozone

    Can someone please prove to me that the Ozone didn't exist prior to the release of CC14. We are now being forced to have reduced power vacuum cleaners which like the joke says "won't collect a lot of dust".

  11. Anonymous Coward
    Anonymous Coward

    NASA is full of hippies who, ironically, don't get civil liberty

    Just because they did "a study" doesn't mean that it's a real problem. We all know what studies look like... at first there was "ozone depletion". Then there was "global warming" - which somehow turned to "climate change", when people noticed that there was no warming at all. And now they have moved on to this CCl4, so we can forget about the whole "climate change" fiasco.

    NASA employs academic types who have never held a real job. They don't understand the realities of business because their organization runs on a grants (from govt which collects taxes from businesses). What effects they see in the lab don't work at global scale... a human is too small compared to the earth. But it's very easy for them to tell everyone to drop everything because we are NASA and we said so.

    In a true free market, there will be no place for NASA.

    1. Rik Myslewski

      Re: NASA is full of hippies who, ironically, don't get civil liberty

      The oft-repeated charge that the term "global warming" morphed into "climate change," as this AC puts it, "when people noticed that there was no warming at all" is a baseless canard. The IPCC — the Intergovernmental Panel on Climate Change — was founded in response to the UN General Assembly Resolution 43/53 adopted way back on 6 December 1988, which uses the phrase "climate change" 14 times and the organizational name Intergovernmental Panel on Climate Change twice.

      Most simply defined, global warming is the cause and climate change is the effect. Oh, and for those of you who prefer actual data over uninformed ranting about "hippies", check out this data set.

  12. e^iπ+1=0

    Blanket

    Hasn't anyone yet figured out that our Sun is going to run out of fuel really soon now, so we need as much CCl4 (and others) as possible to blanket our planet from the cold outside.

    1. Scroticus Canis
      Meh

      "good news for southern hemisphere countries affected by the Antarctic ozone hole"

      What like Antarctica? The hole never big enough to even reach Tierra del Fuego. Not to many inhabitants down there to get burnt up by UV which is particularly low anyway at those latitudes.

      1. Bob Armstrong

        Re: "good news for southern hemisphere countries affected by the Antarctic ozone hole"

        The polar late winter ozone declines have always formed and always will .

  13. Anonymous Coward
    Anonymous Coward

    Just a thought

    Could some of the carbon tetrachloride be from decomposition of polymers in landfills?

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