A case of the vapours: source of ‘climate-active’ organic aerosol particles pinned down

From Forschungszentrum Juelich , comes what looks to be a pretty important discovery about how plant emitted aerosols like Great Smoky Mountains National Park haze comes about and grows large enough to reflect significant sunlight, something climate models don’t yet fully account for.

Nature and Science

Great Smoky Mountains – image from nps.gov

Major enigma solved in atmospheric chemistry

Nature: Researchers discover source of climate-active organic aerosol particles

According to their results, these extremely low-volatile organic compounds consist of relatively large molecules which contain an almost equal number of carbon, oxygen, and hydrogen atoms. The scientists present a plausible explanation supported by numerous experimental findings of how these vapours are formed almost immediately when plant emissions (e.g. monoterpenes) are released into the air. The vapours can then condense on small aerosol particles (starting from clusters of only a few nanometres in diameter) suspended in the air, causing them to grow to around 100 nanometres – at which size they can reflect incoming sunlight and act as condensation nuclei for cloud formation in the atmosphere.

The researchers’ findings have bridged a major gap in knowledge in atmospheric and climate research. “Thanks to our much improved understanding of the role that naturally occurring substances in the atmosphere play in the formation of organic aerosol particles, we will in future be able to make more reliable assessments of their impact on cloud formation and sunlight scattering, and thus on climate,” says Dr. Thomas F. Mentel from Jülich’s Institute of Energy and Climate Research – Troposphere (IEK-8).

The findings are based essentially on measurements performed at Forschungszentrum Jülich in a special 1450 litre glass chamber using a combination of several recently developed mass spectrometry methods, with instruments from Jülich, the University of Helsinki (Finland), and the University of Washington (Seattle, USA). Combined, these produced one of the most comprehensive data sets ever acquired, showing how organic emissions from trees can oxidize to form organic aerosols.

Experts consider a good understanding of the relationship between the increase in soil temperature, plant emissions, aerosol formation, and cloud formation to be essential for predicting future climate development correctly. “Our current research findings will help to improve computer models of the atmosphere and reduce existing uncertainties in climate prediction,” says Prof. Andreas Wahner, director at IEK-8.

“What really made these new findings possible were the new mass spectrometry methods, together with the combined efforts and expertise of all the international collaborators involved”, says the article’s lead author Dr. Mikael Ehn, currently university lecturer at the University of Helsinki. In addition to the institutions at Jülich, Helsinki, and Seattle, the Leibniz Institute for Tropospheric Research (Leipzig, Germany), the University of Copenhagen (Denmark), Aerodyne Research Inc. (USA), and Tampere University of Technology (Finland) contributed to the study.

###

Original publication:

A large source of low-volatility secondary organic aerosols, Mikael Ehn et al; Nature 506, DOI: 1038/nature13032  http://www.nature.com/nature/journal/v506/n7489/full/nature13032.html

Abstract:

Forests emit large quantities of volatile organic compounds (VOCs) to the atmosphere. Their condensable oxidation products can form secondary organic aerosol, a significant and ubiquitous component of atmospheric aerosol1, 2, which is known to affect the Earth’s radiation balance by scattering solar radiation and by acting as cloud condensation nuclei3.

The quantitative assessment of such climate effects remains hampered by a number of factors, including an incomplete understanding of how biogenic VOCs contribute to the formation of atmospheric secondary organic aerosol. The growth of newly formed particles from sizes of less than three nanometres up to the sizes of cloud condensation nuclei (about one hundred nanometres) in many continental ecosystems requires abundant, essentially non-volatile organic vapours4, 5, 6, but the sources and compositions of such vapours remain unknown.

Here we investigate the oxidation of VOCs, in particular the terpene α-pinene, under atmospherically relevant conditions in chamber experiments. We find that a direct pathway leads from several biogenic VOCs, such as monoterpenes, to the formation of large amounts of extremely low-volatility vapours. These vapours form at significant mass yield in the gas phase and condense irreversibly onto aerosol surfaces to produce secondary organic aerosol, helping to explain the discrepancy between the observed atmospheric burden of secondary organic aerosol and that reported by many model studies2.

We further demonstrate how these low-volatility vapours can enhance, or even dominate, the formation and growth of aerosol particles over forested regions, providing a missing link between biogenic VOCs and their conversion to aerosol particles. Our findings could help to improve assessments of biosphere–aerosol–climate feedback mechanisms6, 7, 8, and the air quality and climate effects of biogenic emissions generally.

UPDATE: Figure 4 courtesy of Lance Wallace, who writes in comments:

This does seem to be a blockbuster from Kulmala’s group and others. They used various time-of-flight mass spectrometers to identify what they call ELVOCs (extremely low volatility organic compounds) that are created in the atmosphere and immediately condense on nano-condensation nuclei (nano-CN) particles irreversibly, such that the nanoparticles can grow to eventually become CCN (cloud condensation nuclei) and create clouds. These ELVOCs are large molecules, with example formulae of C10H15O10 or C20H32O12. The main mass spectrometer employed nitrate ions to collide with the particles. Since HNO3 is a pretty common atmospheric constituent, the authors conclude that once the nanoparticles grow to about 1.5 nm (say from a cosmic ray collision or a radon decay) the ELVOCs can continually condense on them to grow them to 50 nm (CCN size) in a matter of hours.

The authors do not mention Kirby or Svensmark, but I wonder if this is the missing mechanism from Svensmark’s 2013 study allowing cosmic-ray-initiated particle growth to proceed to CCN size.

ehn_etal_Fig4

ehn_etal_Fig4_text

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42 Responses to A case of the vapours: source of ‘climate-active’ organic aerosol particles pinned down

  1. Neo says:

    It’s a darn good thing that with this research, once again, “the science is settled.”

  2. DirkH says:

    ” “Our current research findings will help to improve computer models of the atmosphere and reduce existing uncertainties in climate prediction,” says Prof. Andreas Wahner, director at IEK-8.”

    As there is only a 5% remaining uncertainty (the IPCC is 95% certain), we should stop this research, as it is no longer cost efficient or necessary, and concentrate entirely on the computer screens. They tell us the future.

  3. Alan Robertson says:

    That settles it. We must begin the immediate conversion of forests to fuel. The reason for the climate pause has been discovered. Trees are obviously standing in the way of our glorious utopian future. Mann the axes!

  4. kenw says:

    These particles are nothing to sneeze at. (sorry…)

  5. Col Mosby says:

    So what happens if the AGW folks get their way and everyone considers the science settled?
    Sounds like we won’t be needing all those studies and research jobs. Believe it or not, but they inadvertantly are campaigning for their jobs to be eliminated. I wonder if they understand that?

  6. eco-geek says:

    The solution to the monstrous Global Warming Threat is now clear:

    We must burn more fossil fuels to encourage the growth of pine forests through increased CO2 production.

    I always said the environmental movement should get back to the “plant a tree in ’73″ meme (UK).

  7. RH says:

    “Our current research findings will help to improve computer models of the atmosphere and reduce existing uncertainties in climate prediction,” says Prof. Andreas Wahner

    Professor, these are not the kind of improvements the consensus are looking for, but thanks for playing.

  8. u.k.(us) says:

    Great stuff Anthony,
    As long as it doesn’t lead to sensory overload.

  9. Lance Wallace says:

    This does seem to be a blockbuster from Kulmala’s group and others. They used various time-of-flight mass spectrometers to identify what they call ELVOCs (extremely low volatility organic compounds) that are created in the atmosphere and immediately condense on nano-condensation nuclei (nano-CN) particles irreversibly, such that the nanoparticles can grow to eventually become CCN (cloud condensation nuclei) and create clouds. These ELVOCs are large molecules, with example formulae of C10H15O10 or C20H32O12. The main mass spectrometer employed nitrate ions to collide with the particles. Since HNO3 is a pretty common atmospheric constituent, the authors conclude that once the nanoparticles grow to about 1.5 nm (say from a cosmic ray collision or a radon decay) the ELVOCs can continually condense on them to grow them to 50 nm (CCN size) in a matter of hours.

    I uploaded a crucial figure from their article to Dropbox showing the relative power of ELVOCs vs other promoters of particle growth.

    https://dl.dropboxusercontent.com/u/75831381/Figure%204%20from%20Ehn%20et%20al%202014.pptx

    The authors do not mention Kirby or Svensmark, but I wonder if this is the missing mechanism from Svensmark’s 2013 study allowing cosmic-ray-initiated particle growth to proceed to CCN size.

  10. O. Olson says:

    So Reagan was right after all. Again.

  11. Chuck Nolan says:

    “Our current research findings will help to improve computer models of the atmosphere and reduce existing uncertainties in climate prediction,” says Prof. Andreas Wahner, director at IEK-8.
    ———————————————-
    So they are predictions, eh?
    cn

  12. hunter says:

    O. Olson makes the point for those who know history. That trees emit significant amounts of organics has been known for sometime. When President Reagan mentioned this as part of why he was not so worried about come pollution issues, the same geniuses who are selling AGW attacked him viciously over this. That this is considered an important paper implied heavily that we have lost knowledge in the age of big greeen political power, not gained it.

  13. Berényi Péter says:

    Right, arboreal pollution is certainly a most serious issue.

    At a biometeorological conference at Rutgers, University of Nevada Professor Frits Went stated flatly that trees foul the air with ten times more pollutants than all of man’s fires, factories and vehicles.

    Such trees as fragrant pine and plants such as pungent sage produce the “blue haze” that occurs during summer, even over relatively uninhabited areas of land. They emit molecular substances known as terpenes

    It was in 1966.

    Since this ground breaking discovery almost half a century has passed, therefore it is high time for EPA to issue endangerment findings on it and calculate social cost of forestry. Mind you, trees are also competing with solar panels through a process called “shade pollution” and they are the primary cause of forest fires. It would be best perhaps to cut down all those foul creatures and sequester their carbon laden remains in abandoned underground coal mines.

  14. Louis Hooffstetter says:

    Like CO2, I simply don’t consider these low volatile aromatic compounds to be pollution. My favorite fragrances are Christmas trees and the Jemez Mountains (New Mexico) in summer.

  15. “Our current research findings … will blame climate change for more/less/same # of particles depending on what excuse we need to use today.” [Fake But Accurate Quote]

  16. jim2 says:

    So, more CO2 means, bigger trees, and more aerosols. Interesting. Isn’t that called a negative feedback? You never know what climate science will call it.

  17. MattS says:

    @Jim2,

    Actually, it’s easy to predict what the warmists will call it. A positive feed back. Higher temps->fewer smaller trees->less aerosols. :)

  18. R. Shearer says:

    You’re so prene; Isoprene.

  19. Pamela Gray says:

    Here in NE Oregon, we don’t call them “The Blue Mountains” because the trees are blue. This seems to be another one of those research projects born on the wave of grant money slop. Basically, it is a new generation rediscovering something known by previous generations learned enough to name mountain ranges by the gasses they give off.

  20. Stu Miller says:

    Back in the early 70′s, some meterorologist friends of mine were doing air quality surveys for the state of Washington in the Snoqualmie Pass area. These surveys were for an EIS for improvement of the freeway thru the pass. They also surveyed air quality a couple of valleys over from the pass. They were very amused to note that the VOC levels measured in the pristine valley were much higher than along the highway.

  21. jim2 says:

    @ MattS says:
    February 26, 2014 at 5:05 pm

    FAIL!
    Trees love more CO2. They even use less water as CO2 concentration increases.

  22. Outtheback says:

    Ok, so it is not CO2 after all but humans chopping down too many forests in the late 70′s which caused the change from cooling and next Ice Age to warming and all burning to death.
    Lucky that we chopped down those trees then otherwise the icecap would be down to Atlanta already.
    As there is even less forest now it does not make sense that this will have more of a cooling effect then what it did in say 1985.
    Come to think of it, the world would never have gotten out of the LIA, actually how did the MWP or the RWP happen with all those trees around.
    Next week another reason why the increase stopped.
    So we have had
    hiding in the oceans
    trade winds
    volcanoes
    trees

    Next week: the air disturbance of birds flying causes the updraft of warm air which then allows the heat to escape and thus slowing down any further increases in temps. Conservation methods are working we now have more birds (sadly not) then 40 years ago, the foresight of those people stopped the warming, they are our heroes.
    Two weeks from now: the air disturbance from wind turbines is causing as per above, we need more of those.
    Three weeks from now: as there has now been a kind of grass GM’ed that stops ruminants from excessive degassing it has stopped the warming trend

  23. MattS says:

    @jim2,

    “Trees love more CO2. They even use less water as CO2 concentration increases.”

    I know that and you know that, but the alarmists will still bend themselves into pretzels trying to spin this as a positive feedback.

  24. Crispin in Waterloo says:

    Something not noted is the large number of water droplets that condense from evaporation of water that goes along with the VOC’s. Gases and particles are deposited on and in these fog droplets. The amount of water involved can be very large. It was noted by Dr St Barbe Baker in the 1920′s that the giant sequoia harvested water from the air by first pumping out about 500 gallons each to super-saturate the air causing it to rain on days when it never would. It depends (totally) on having enough trees in a group to produce this effect, as one tree cannot do this on its own. It was one of the first recognized microclimates.

    The blue haze is not really composed of particles below 0.1 microns (100 nm). They would be too small to reflect visible light. The blue haze is visible because of the water droplets large enough to reflect blue light (short wavelength light), on which are condensed a variety of things including blue dyes, basically.

    As particles grow they can reflect or refract longer wavelengths until eventually they can produce a rainbow at about 1 micron diameter. That is why clouds are white: big particles of reflective water.

    Many of the VOC’s are combustible. Pulling them into an internal combustion engine provides a tiny amount of free additional heat (and cleans the air).

  25. RACookPE1978 says:

    Stu Miller says:
    February 26, 2014 at 6:00 pm

    Back in the early 70′s, some meterorologist friends of mine were doing air quality surveys for the state of Washington in the Snoqualmie Pass area. These surveys were for an EIS for improvement of the freeway thru the pass. They also surveyed air quality a couple of valleys over from the pass. They were very amused to note that the VOC levels measured in the pristine valley were much higher than along the highway.

    And,
    Crispin in Waterloo says:
    February 26, 2014 at 6:50 pm

    There is a very strong, very pronounced summertime “ozone mountain” (as opposed to the Antarctic’s famed high-altitude “ozone hole” of 1970-80′s decadal fame) across the entire southeastern US (NC-SC-GA-AL-MS) as each of the trillions of small, rapidly-growing pine trees emits its own ozone every summer. Regardless, your favorite EPA and the DOT require very expensive gasoline varietites be brewed each summer for Atlanta to “cut the ozone levels down” ….

    But, the Good Gail Combs of the “Tar Heel State” to our east just may recognize some of these “turpentine” vapors as a long-needed financial foundation of the lower east coast back in the days of the Royal Navy and its sailors. …

  26. NRG22 says:

    Wow, I just got an education indirectly from this article. Not being a scientist I don’t always understand what I read here. So I looked up terpene α-pinene: turpentine, essential oils, got it. Interestingly there was a link to High Times magazine about the terpenes in marijuana. That article mentioned CO2 extraction. Looking that up lead me to Organa Labs use of CO2 extraction for cannabis concentrations. That lead me to a YouTube video on how to do it at home with dry ice. That lead me to Wikipedia to read up on how CO2 is formed into dry ice. Burning fossil fuels is one way. (I had no idea CO2 was used in so many food items)

    But now I have a question: are the Greenies, who have a tendency to be the ones that smoke pot, helping or hurting the planet?

  27. FrankK says:

    In Australia there is dominance of Eucalyptus oil vapour (C10H18O) due to the abundance of eucalyptus trees that can render distant mountains a blue colour that I imagine would work the same way.

  28. MFKBoulder says:

    RACookPE1978 says:

    rapidly-growing pine trees emits its own ozone every summer.

    ###########################
    That’s new: prine trees emitting Ozone?!?!

  29. Admad says:

    eco-geek says:
    February 26, 2014 at 2:03 pm
    I always said the environmental movement should get back to the “plant a tree in ’73″ meme (UK).

    You forgot the follow-up “buy a saw in ’74″. Lulz.

  30. johnmarshall says:

    So, when temperatures rise VOC production increases so reducing temperatures. Another NEGATIVE FEEDBACK.

  31. michael hart says:

    Can’t see anyone getting very surprised. Atmospheric chemistry is complex, and the diversity of isoprenes is immense. These sort of reactions are always known/suspected to be going on.

    But until someone has the funding/resources to look at it, you won’t see much research, published or otherwise.

    That leaves much space for others to publish alarmist speculation, restricted only by their personal ethics and morals.

  32. FXM says:

    Microbes in the ocean also release cloud and rain making chemicals when the water gets too warm. Bacteria that live on plants (and cause a great deal of damage from frost) can cause water to freeze above 0 C, and when it is hot they are lifted into the atmosphere, where they cause ice to form in clouds, causing it to rain.

  33. Myron Mesecke says:

    Sounds like the Earth is more self regulating than we give it credit for.

  34. Some more background of the failure of models to take into account the natural VOC emissions from trees:
    http://acmg.seas.harvard.edu/publications/heald_2005.pdf
    Heald e.a. found that natural SOA’s (secondary organic aerosols) made from terpenes were underestimated a factor 2 at the boundary layer and a factor 10-100 in the free troposphere by atmospheric chemistry models. That means that much of the cooling attributed to human aerosols (recently the scapegoat of Solomon e.a. to explain the “pauze”) is in fact caused by natural aerosols…

    Further, from Science:
    http://www.sciencemag.org/content/312/5771/261.abstract
    aerosols above European forests
    And I have my doubts about the role of human SO2 emissions on aerosol formation, as can be seen in comment #6 at the RC discussion, in the early period that they didn’t censor halve of my comments:
    http://www.realclimate.org/index.php/archives/2006/02/an-aerosol-tour-de-forcing/

  35. bill_c says:

    Ferdinand,

    I think one of the consequences of reducing human SO2 emissions is that the ammonia and nitrate species compete more effectively to become cloud condensation nuclei.

  36. DesertYote says:

    I thought that the mechanism by which fog eaters (e.g. Gum Trees, Redwoods, and Cypress) extract moisture was well understood decades ago. Once again inconvenient knowledge has been deliberately forgotten all for the sake of the agenda.

  37. old engineer says:

    RACookPE1978 says:
    February 26, 2014 at 10:46 pm
    =========================================================================

    As RACook says, the fact that terpenes from pines cause natural air pollution has been known for a long time in the Southern U.S. The fact that controls on human caused ozone in the Atlanta area produced no improvement in ozone levels, led to the formation of the Southern Oxidants Study back in the mid-eighties. The study has been ongoing for a couple of decades. For those interested, google “Southern Oxidants Study.”

    Dr. Havery Jefferies at the University of North Carolina at Chapel Hill for many years ran a outdoor “smog chamber” (he still may for all I know) which permitted the study of atmospheric reactions with sunlight in a confined chamber. Some of his studies involved terpenes. In fact, I see that the topic of a doctoral dissertation in 2007 from UNC was on the subject of the Nature paper discussed above.

    The disseration: “Secondary Organic Aerosol (SOA) Formation from Monoterpene Ozonolysis in the Presence of Inorganic Aerosols: Acid Effects on SOA Yields” by Amanda Laura Northcross.
    See: https://cdr.lib.unc.edu/indexablecontent/uuid:ff50bc08-1e79-4264-b6ed-4c23b4a7023b

    So the Nature paper seems to be just another study, possibly adding a little more understanding to things that have been known about for some time.

  38. Robert A. Taylor says:

    If I am not mistaken this is a rehash of 1970’s and prior science with a little additional precision. At least I remember reading multiple papers about aerosols released by trees and other plants, and their reaction products.

  39. mbur says:

    “…vapors: source of ‘climate active’ organic particles pinned down”
    So, plants/animals grow over time into an existing climate and emit organic compounds and then those change that climate?
    Is that climate change?
    Thanks for the interesting articles and comments.

  40. Keith Minto says:

    Interesting article.
    The Blue Mountains west of Sydney is a prime example of this effect. I was in Morton National park on the weekend and had blue mist taking the edge off my photographs.This article (.pdf) gives an image of the Blue Mountains plus an overview of VOCs by 2007.

    Knowledge of organic composition in the back
    ground atmosphere lagged behind urban pollution
    studies. In 1960, Went theorized that biogenically
    emitted VOCs created the blue haze observed in the
    atmosphere above many forested regions, such as
    the Blue Mountains in Australia.

    Subsequent research has shown that, on a glob
    al scale, emissions of VOCs from vegetation are an
    order of magnitude greater than those from petro chemical production and use.

    Even in some urban environments, biogenic VOC emissions were shown to be as important for regional
    photochemical ozone production as anthropogenic VOC emissions.

    Very interesting area for study.

  41. Richard D says:

    Very interesting area for study.
    _==================
    Nice place to live, too. Apparently we were run out – the usual suspects – from VA to NC where we did not prosper and then to TN then KY. Then MO, TX and CA and back to KY. And now the southern Appalachian Mountains, again. It’s deja vous, all over again.

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