SLACing the soot

From the DOE/SLAC National Accelerator Laboratory

X-ray vision exposes aerosol structures

Laser probes microscopic components of air pollution

A new investigation using X-rays from the Linac Coherent Light Source has helped researchers better understand the structure of airborne soot particles. These simulated particles, based on previous research models, illustrate the expected fractal structure of soot particles in the air. The latest research shows that soot particles produced as aerosols can be noticeably denser than the ones shown here. Credit: Duane Loh & Andy Freeberg, SLAC National Accelerator Laboratory

Menlo Park, Calif. — Researchers at the U.S. Department of Energy’s (DOE) SLAC National Accelerator Laboratory have captured the most detailed images to date of airborne soot particles, a key contributor to global warming and a health hazard.

The discovery reveals the particles’ surprisingly complex nanostructures and could ultimately aid the understanding of atmospheric processes important to climate change, as well as the design of cleaner combustion sources, from car engines to power plants.

The study, published in the June 28th issue of Nature, also pioneers a method for studying a broad range of individual particles, such as cells or proteins, and opens up exciting possibilities in the study of aerosol dynamics using highly focused X-ray lasers, such as SLAC’s Linac Coherent Light Source (LCLS).

“Our study shows that LCLS can drive a paradigm shift in imaging airborne particles, allowing us to look at them one at a time instead of using a composite of many different particles,” said Duane Loh, the lead author of the study and a postdoctoral scholar at SLAC and Stanford University’s PULSE Institute for Ultrafast Energy Science. “We now have a richer imaging tool to explore the connections between their toxicity and internal structure.”

Soot and similar particles – especially those 2.5 microns or less in diameter, which are the most dangerous to human health – are difficult to image while airborne. When placed on a surface for examination with a microscope, they tend to clump together and lose their shape.

In this experiment, researchers wafted individual soot particles up to 3.25 microns in diameter into the path of the LCLS laser beam. Its laser pulses are so brief that they captured information about the particles, only millionths of a meter across, in the quadrillionths of a second before they blew apart.

They found that no two are alike. Like magnified snowflakes, soot particles exhibit similar patterns of complexity at different scales, which is characteristic of fractals. Other research methods have probed the fractal properties of soot, but the LCLS’ ability to examine those of individual soot particles, airborne and in their natural state, revealed surprising diversity and complexity in their fractal dimensions. Such observations can help validate the various models used to describe these soot particles.

The results make scientists wonder what diversity of forms will be discovered if particles produced in real-world, “messy” environments, such as a car’s combustion engine or a candle flame, are imaged one at a time. The team is analyzing data from experiments at the LCLS that examined soot from diesel emissions as well as other types of airborne particles.

A primary long-term goal of the research is to take snapshots of airborne particles as they change their size, shape and chemical make-up in response to their environment, said Michael Bogan, a staff scientist at PULSE and leader of the international research team.

“Scientists can now imagine being able to watch the evolution of soot formation in combustion engines from their molecular building blocks, or maybe even view the first steps of ice crystal formation in clouds,” he said.

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The research team included contributors from SLAC, DESY, Lawrence Berkeley National Laboratory, the Max Planck Institutes, the National Energy Research Scientific Computing Center, Lawrence Livermore National Laboratory, Cornell University, the University of Hamburg, Synchrotron Trieste and Uppsala University. LCLS is supported by DOE’s Office of Science.

SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the U.S. Department of Energy Office of Science. To learn more, please visit www.slac.stanford.edu.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

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29 Responses to SLACing the soot

  1. “working to address some of the most pressing challenges of our time. ” As interesting as this is, one wonders how often that term can be used and also the benefits from this study. It will be interesting to see where this all goes or whether it is just another attempt at removing fossil fuels with no replacement in the near future.

  2. Kurt in Switzerland says:

    Cool. Sounds like another bottomless research budget. I hope that someday they figure out whether soot heats or cools, also what is “natural” and what isn’t (though I’m not holding my breath). Next in line: what can be done about it, and please: benefit/cost ratios, finally!

    Kurt in Switzerland

  3. steveta_uk says:

    Now we have this “paradigm shift in imaging airborne particles, allowing us to look at them one at a time instead of using a composite of many different particles” can we expect the GCMs to be updated to model each individual worldwide soot particle?

    I think the UK Met Office will need a bigger computer ;)

  4. Dear Anthony Watts,
    Could you please explain scientifically how the soot can cause global warming? that is impossible, by considering the mehtods of heat transmission. Pollution is bad for health, that’s ok but not global warming.

  5. indrdev200 says:

    Dear Anthony Watts,
    Could you please explain scientifically how the soot can cause global warming? that is impossible,
    by considering the methods of heat transmission. Pollution is bad for health, that’s ok but not global warming.

  6. Jimbo says:

    Menlo Park, Calif. — Researchers at the U.S. Department of Energy’s (DOE) SLAC National Accelerator Laboratory have captured the most detailed images to date of airborne soot particles, a key contributor to global warming and a health hazard.

    Yes, but how much? Same goes for Co2.

  7. Bill says:

    This is great news. In 20-30 years we may be in a position to analyze and explain the effects of soot and aerosols on human health and on climate. I look forward to the new climate models in 30 years that will be trustworthy.

  8. Bill Tuttle says:

    Soot and similar particles – especially those 2.5 microns or less in diameter, which are the most dangerous to human health –

    So, the next Big Lie is well on its way.

    http://wattsupwiththat.com/2012/06/04/the-epas-unethical-pm2-5-air-pollution-experiments/

    Interesting science, even though the premise — “We now have a richer imaging tool to explore the connections between their toxicity and internal structure” — is bullsh*t.

  9. They write:
    “Laboratory have captured the most detailed images to date of airborne soot particles, a key
    contributor to global warming and a health hazard.”

    =========================

    And there was I under the impression that particles cause global cooling, – so now they’ll have to figure out the various absorption rates of all the different airborne particles in the complete Troposphere. – How dark/light have particles got to be to absorb or reflect?

    My forecast is there are much more “global-warming soot-particles” (GWSP) aloft – and that the concentration is increasing – than there is of the other “reflecting kind”

    More funds are needed me thinks.

  10. gail Combs says:

    OH great new research do out just-in-time to link mankind to GLOGAL COOLING

  11. Mike says:

    “These simulated particles, based on previous research models, illustrate the expected fractal structure of soot particles in the air. “

  12. ferdberple says:

    Soot and similar particles – especially those 2.5 microns or less in diameter, which are the most dangerous to human health – are difficult to image while airborne.
    =====================
    The long time researcher that published his detailed study showing that 2.5 micron particles were not hazardous was fired from his job. His research being bad politically for the EPA and Obama administration in their efforts to get rid of coal as a power source in the USA. In their ongoing effort to drive US energy prices higher and increase reliance on foreign oil supplies. Coal being the one energy source the US has in ample supply, the economic defeat of the US requires coal is banned as an energy source domestically in the US.

  13. Hard to get global warming scares to come to an end when so much money and so many jobs are involved in keeping it going.

  14. old engineer says:

    Actually this is very good news for those studying atmospheric aerosols and particles. Twenty five years ago, when I was investigating jet engine exhaust visibility for the U.S. Navy, I was looking for a laser instrument that would count and size particles down in the 0.1 micron size. These instruments are based on measuring the scatter angle of the laser light. One instrument manufacturer told me trying to use a visible light laser to measure particles that small was like trying to “scatter radio waves with a basketball.” That what I needed was an x-ray laser, which didn’t exist at the time. Now apparently they do.

    How this new knowledge is used the another matter. But we should all applaud advances in measurement ability, since, as Lord Kevin said, “Measurement is the basis of all knowledge.” That’s because measurements produce real data.

  15. Under the picture “These simulated particles, based on previous research models” Wow what reality and the need for more research dollars?

  16. Roger Carr says:

    ferdberple says: “The long time researcher that published his detailed study showing that 2.5 micron particles were not hazardous was fired from his job. …”

         Remember reading that story, Ferd.
         We are not really living 1984 by George Orwell, so much as in Alice in Wonderland by English author Charles Lutwidge Dodgson (Lewis Carroll), who also noted the impossible “Then the bowsprit got mixed with the rudder sometimes.”
         Only it’s not impossible in 2012, is it… just another hidden obscenity.
         Out them, and out them, and out them…

  17. Ric Werme says:

    Dev Bahadur Dongol says:
    June 28, 2012 at 2:14 am

    > Could you please explain scientifically how the soot can cause global warming?

    Basically, soot is dark, dark decreases Earth’s albedo.

    The most important process may be soot that settles on snowpack, that absorbs sunlight, melts the snow around it, water drains away, but the soot remains. Eventually the snow melt finishes earlier than usual, allowing the ground to thaw earlier, etc.

    I can see something like that in old snow piles by neighborhood streets. Snow that has sand or dirt mixed in changes to “corn snow” (granular ice) and melts much faster than clean snow a meter away.

    Soot in the air absorbs sunlight and warms the air. A similar process with dust blowing off the Sahara desert warms the troposphere, but blocks enough light so the sea surface doesn’t warm as quickly as it might. This often delays the start of the Cape Verde hurricanes due to the cooler water and more stable (less convective) atmosphere.

  18. Katherine says:

    These simulated particles, based on previous research models, illustrate the expected fractal structure of soot particles in the air.

    If they actually managed to captured detailed images of the structure of soot, why are they using “simulated particles” as illustration in the press release? Why not use an actual image from the experiment?

    And, gosh, soot promotes global warming? If they can’t bother to keep up with relevant research, why should anyone give weight to their findings?

  19. wsbriggs says:

    I’m not concerned about soot as a source for GW, more as a possible contributor to lung cancer. Of course with the soot, it helps to be a smoker if you really want to improve your odds for getting LC.

    As far as soot is concerned, I suspect that over time we’ll discover that the particles have organisms and other chemically active elements which bond them and purge the from the air – rain being one of them.

  20. Ed Mertin says:

    How can soot cause global warming?
    The US Air Force measurements of the stratosphere in the 1930’s showed it to be clear. Meanwhile, in the troposphere there was lots of volcanic soot…

    http://www.volcano.si.edu/world/largeeruptions.cfm

    RABAUL New Britain 1937 May 29 4?
    KUCHINOERABU-JIMA Ryukyu Islands (Japan) 1933 Dec 24 4?
    SUOH Sumatra (Indonesia) 1933 Jul 10 4
    KHARIMKOTAN Kuril Islands 1933 Jan 8 5
    AZUL, CERRO Central Chile 1932 Apr 10 5+
    FUEGO Guatemala 1932 Jan 21 4
    ANIAKCHAK Alaska Peninsula 1931 May 11 4
    KLIUCHEVSKOI Kamchatka Peninsula (Russia) 1931 Mar 25 4
    KOMAGA-TAKE Hokkaido (Japan) 1929 Jun 17 4

  21. fhhaynie says:

    To me it looks like they are observing airborn agglomeration of sub-micron particles. Anthropogenic soot is spherical. Much of my research at EPA was on aerosols. We used scanning electron microscopy to determine the size distribution of particles. Google Fred H. Haynie + particles.

  22. David OHara says:

    In the mid 80s in my graduate work on electrostatic precipitation, we collected charged fly ash particles under a low electric field. Fly ash particles in the air can be expected to be weakly charged and behave similarly. We then examined them under a Scanning Electron Microscope. We saw exactly this fractal structure. The coolest pics were stereoscopic pairs. There was some evidence that higher electric charge leads to a denser fractal.
    This work was NOT publishedc

  23. David OHara says:

    Count and size such tiny particles? The device I used for my graduate work was invented by Dr S.J. Clements (currently at Apalachian State Univ) used a laser to illuminate a cell which was basically a Millikan oil drop apparatus. However, a transverse oscillating field caused the particles to oscillate back and forth and this was recorded by a video on a microscope. With this device, we could not only get the charge but radius as well.

  24. Crispin in Waterloo says:

    Dev Bahadur Dongol says:
    “Could you please explain scientifically how the soot can cause global warming? that is impossible, by considering the mehtods of heat transmission. Pollution is bad for health, that’s ok but not global warming.”

    +++++++++++

    All right, you (vibrant) lot, before you get out of hand assuming things for which you have no data, let’s get some perspective on particles.

    They are measuring quite large particles (over 3 microns). The fact they are agglomerated shows they are made up of smaller particles that ‘grew’ or stuck together (which they do quite well, BTW). A giant dendritic particle can have thousands of smaller members on its team. See slide 8 of http://www.dri.edu/images/stories/editors/leapfrog/techprog/IIf_3_Annegarn.pdf for a biggie. That is a coal combunstion particle measured about 1 km downwind, after it has had time to grow. They fall to earth quite quickly.

    Black carbon (BC) particles definitely heat the air around them because they are, well, black. As mentionedin messages above, particles down to 0.1 microns can be measured using visible light because 0.1 microns is the cut-off point for visible light interacting with the particle. It’s a wavelength thing. It scatters (bounces) visible light so they can be measured either by their shadows or reflections. Both methods are used, even determining the shape and count at a rate of billions of particles per cubic centimetre. People are clever!

    Organic carbon particles might be formaldahyde droplets or boiled lignin. Could be lots of things. A particle is not necessarily a solid, it can be a sticky blob of tar, condensed water (fog) or a tiny piece of silica dust from the combustion of rice hull. Even if dense, they float around so they are called aerosol particles.

    Particles smaller than 4.0 microns are absolutely, definitely a health hazard because they are small enough to penetrate deep into the lungs (respirable). That is where smoker’s lung cancer and silicosis and black lung and all those disease come from. This is not CAGW, this is well established environmental exposure to respirable contaminants with easily traceable health consequences. The first identified occupational cancer (testicular cancer of chimney sweeps) was traced to fine particle inhalation. Women and small children who inhale smoke from wood fires get upper respiratory infections in direct relation to the amount inhaled (check Dr Kirk Smith’s site, UCBerkeley). In fact one way to show that improved stoves are having an effect is to monitor URT infections at local clinics.

    Diesel, biomass and coal (and other) combustion produce very small nanoparticles, many of which were not detectable before sub-light wavelength equipment became available. Raindrops form on them. The big +10 micron particles produced by power stations come from blowing the ash into the air (fluidised beds are notorious for this) not from combustion processes. Badly burned damp wood can manufacture a host of chemicals which condense into wet particles that can be inhaled. Bad things result. Good combustion can be amazingly clean. Forest fires are extremely dirty in all size ranges.

    The hint that BC is causing warming points to what was known over a decade ago – that the influence of BC aerosols is probably much greater than expected. You can imagine how effective a soft coating of black soot is as a heat absorber on a solar water heater. The colour is so densely black you can hardly see it is there. Well, scatter them into the air, they are even more effective as individuals.

    The CAGW implication is that CO2 must be having a smaller effect than has been assumed for it. If there is any quantum of heating, and it has to be apportioned to various forcings, and BC is really large, then obviously the others are of lesser effect. Basically, for each and every Watt attributable to Black Carbon, one must be subtracted from CO2. So you see the warmist’s dilemma. Admitting that BC has a powerful heating influence means simultaneously admitting CO2 is not as powerful, unless you are double-dealing in the hope that no one notices. I noticed years ago. Those pointing out the heating effect of BC had to be very careful not to make too much noise about the obvious implication for CO2 forcing, while simultaneously raising the profile of a contaminant that is definitely health related, and about which something can easily be done at relatively low cost. All this is bad news for GW alarmism as a church. The ‘debbil’ turned out not to be under the bed or in the closet.

    So…connect the (jet black) dots. Some reseachers will benefit and others will lose. At least this is a switch to solving a real problem. What a breath of fresh air!

  25. squodgy says:

    [SNIP: Sorry, but we don't discuss chemtrails here. Please check our site policy here. -REP]

  26. Crispin in Waterloo says:

    @squodgy says:

    [SNIP: Sorry, that was a nice reply, but squodgy's comment was approved by accident. We don't discuss that topic here as per site policy. -REP]

  27. iamreplete says:

    Research such as this could well result in better ways of handling combustion particles, and so perhaps result in better combustion practices, all of which may well result in less fuel being consumed per power unit, or, of course, more power from the same.
    I do not see, at this point, why the findings can be associated with the CAGW scare, certainly not to the extent that the advent of the motor car was associated the decline in horse manure in our streets.
    The rise in automobile usage was directly connected with the decline of animal waste in our streets, in fact caused it.
    But the study of exhaust particles at fractal level may be found to to have nothing to do with CAGW.
    Don’t forget that each individuals breath is an exhaust. Anything which might improve our body’s way of handling our lungs working is to be welcomed.

  28. George Steiner says:

    Under the photograph it says ” these simulated particles”.
    How were these particles simulated?

  29. Adam says:

    Could someone please construct a non-UHI index, perhaps using surface station project data? Include only well-situated stations distant from urban centers.

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