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Thread: Yet more doubt on diesel

  1. #1

    Default Yet more doubt on diesel

    [Preemptively I want to say, I'm not trying to rehash anything here. This is honest to goodness new media-worthy research that is relevant not only to trolleys, but to walkable streets, private motor vehicles, BRT, LRT, life itself, and health care costs, as well as hopefully to the current election. About a year ago somewhere or other, I linked to information regarding cancer and diesel. I also mentioned diesel's links to other health problems, but without citation. This article released last week concerns previously unpublished research into diesel's relationship to heart disease.

    Also please note that the study was using "Clean Diesel".] -J.B.


    Roadside diesel pollution poses heart danger: study
    Wed Sep 12, 2007 10:25pm BST


    By Gene Emery

    BOSTON (Reuters) - Air pollution reduces blood flow and interferes with the body's natural ability to break up blood clots, researchers said on Wednesday in a finding that may help explain why pollution can cause heart attacks.

    And the study, published in the New England Journal of Medicine, also suggests that heart patients trying to shape up might do their exercising away from traffic.

    The researchers tested 20 male volunteers, all of them heart attack survivors, who pedaled an exercise bike while breathing diluted fumes from the exhaust of an idling Volvo diesel engine.

    The exposure was comparable to the pollution levels found while driving in traffic.

    Doctors already know that long-term exposure to air pollution increases the risk of heart problems. The World Health Organization has estimated that it causes 800,000 premature deaths worldwide each year.

    The new study looked at one particularly suspect element of air pollution and how it affected people over the short term.

    Nicholas Mills of Britain's Edinburgh University and his colleagues found that when the volunteers breathed diesel fumes, their hearts were far more likely to be starved of oxygen than when they were breathing clean air.

    And when they tested the blood of the men, they found that the fumes inhibited the body's natural system of breaking down the clots that can spark a heart attack or stroke.

    That may explain the results of population-based studies showing that air pollution increases heart problems, they said.

    It is not known exactly why the hearts became starved of oxygen or which substance in the exhaust was responsible for the effects.

    "The study was specific in evaluating the effects of dilute diesel exhaust, an extremely complex mixture of particles and gases; it is not possible to glean which constituents of diesel exhaust were responsible for the observed effects," Dr. Murray Mittleman, of Boston's Beth Israel Deaconess Medical Center, wrote in a commentary.

    Although the study was only done on men with a previous heart attack, "these findings may represent the tip of an iceberg" and apply to anyone at risk for a heart attack, he said.

    Exercise is already known to be beneficial and it especially decreases the risk that a person will have a heart attack while exerting themselves, Mittleman said.

    "The risk-benefit ratio may be optimized if people exercise away from traffic when possible."

    Reuters 2007. All rights reserved.

    http://uk.reuters.com/article/health...28936620070912

    ------------------------------
    Here also is a more in-depth but less media friendly article:

    http://www.medicalnewstoday.com/articles/82347.php

    And here is the abstract for the report itself, in the New England Journal of Medicine:

    "Ischemic and Thrombotic Effects of Dilute Diesel-Exhaust Inhalation in Men with Coronary Heart Disease"
    http://content.nejm.org/cgi/content/short/357/11/1075

  2. #2
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    Default Re: Yet more doubt on diesel

    Quote Originally Posted by JayBee
    "The study was specific in evaluating the effects of dilute diesel exhaust, an extremely complex mixture of particles and gases; it is not possible to glean which constituents of diesel exhaust were responsible for the observed effects," Dr. Murray Mittleman, of Boston's Beth Israel Deaconess Medical Center, wrote in a commentary.
    In an occupational setting, diesel fumes are monitored for carbon monoxide CO (25 ppm 8-hour Occupational Exposure Limit), oxides of nitrogen NO and NO2 (25 and 3 ppm 8 hour OEL respectively) and for benzene solubles (1 ppm 8 hour OEL).

  3. #3

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    I don't think he's saying that the different constituents of diesel exhaust can't be measured/monitored, just that to discover exactly which compound or combination of compounds are primarily responsible for the real effects measured would mean both enlarging the scope of the experiments exponentially, as well as probably having to create very much less common air quality manipulating apparati (sp?) than an idling Volvo. Such an experiment would certainly require a completely different and in my estimation, unlikely, level of funding.

    The findings are clear enough in that diesel exhaust constitutes a serious risk in heart disease by clearly showing two of its mechanisms therein. It's very good science about an important issue.

    Hopefully it gives some food for thought anyway, but for me, the seemingly underestimated health effects of diesel are the number one reason I support trolleys to replace them wherever feasible. (Number two being economics, but that's another thread.)

  4. #4
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    Did anyone analyse for similar effects in gasoline engine exhaust?

  5. #5

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    Westport Innovations out of Vancouver with Cummins (Westport is partly owned by Cummins) build natural gas engines that operate on essentially modified diesel engine designs. They are used in trucks and buses and I'm surprised that it's technology that's being ignored as an alternative to diesel. I think it's still being 'proved' but hundreds if not thousands of buses with these engines are in place around the world.

    Their web site is something like www.westport.com or .ca. And there's probably other companies doing the same.

  6. #6

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    Scott:

    I don't know, but as it says in the article in the second link of the original post, the scientists are interested in trying to test the hypothesis that it is the fine particles in exhaust, rather than the gaseous components, that are primarily responsible for such effects. They noted that diesel exhaust contains between 10 and 100 times the number of particles that gasoline exhaust contains, thus would cause more measurable results and was chosen for the experiment. If the hypothesis is correct, diesel would seem to be between 10 and 100 times worse for the effects measured. I presume that their next experiments will be to try to separate the particles from the fumes somehow, and repeat the tests.

    I'll gladly post any more information I find distinctly important about the topic, if I come across it, as should anyone else, of course. However, from the stuff I've read on diesel and cancer for example, I seem to remember that it was considered at least an order of magnitude more dangerous than gasoline exhaust as well. Personally, while there could be health issues with gasoline engines, I'm convinced they're a distinctly lower priority than diesel.

    (and in every case, both are clearly inferior to electricity. )

    KC
    I also like natural gas, as it seems healthier than either diesel or gasoline and I've also heard is better on CO2 than other fuels [hack chemistry warning] because it mostly consists of methane (CH4) which of course has four carbon-hydrogen bonds to release energy, yet only produces one molecule of CO2 per molecule of methane, which is the lowest possible CO2:energy ratio from that family of hydrocarbons.

    The problems usually associated with natural gas are the cost per kilometre and in vehicle design for large capacity fuel tanks. Naturally health is more important, but how committed are we really?

    (and besides, electricity is both healthier and cheaper anyway... )

  7. #7
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    It's a question about marginal benefits. How much marginal benefit does running trolleys provide to the air quality in Edmonton vs. running Diesel busses. At what cost?

    Coal fired power plants produce particulates as well, albeit, it is more economical to install high efficiency scrubbers on projects of that size. I understand the afterburner technology on many new diesels (that came out only in the current year!) greatly reduces particulate emissions. -> The particulates are trapped in a filter of some kind, and at intervals additional fuel is added to the exhaust to burn the particulates off.

    Diesel buses have certain advantages over trolleys. Trolleys have certain advantages over diesels. The main "pollution" advantage is a relocation of pollution - but certainly, additional vehicles and costs are associated with maintaining the lines.

    It is a question about the marginal return on an investment - maybe it is better to distribute the additional funding to something like an initiative to get high pollution vehicles off the road. Even if we didn't mess with 90% of "old vehicles" but just the ones that belch clouds that cloud the rest of us in our vehicles, that would probably have a high return on investment. Perhaps that is a better place for funds.

    Quote Originally Posted by JayBee
    Scott:

    I don't know, but as it says in the article in the second link of the original post, the scientists are interested in trying to test the hypothesis that it is the fine particles in exhaust, rather than the gaseous components, that are primarily responsible for such effects. They noted that diesel exhaust contains between 10 and 100 times the number of particles that gasoline exhaust contains, thus would cause more measurable results and was chosen for the experiment. If the hypothesis is correct, diesel would seem to be between 10 and 100 times worse for the effects measured. I presume that their next experiments will be to try to separate the particles from the fumes somehow, and repeat the tests.

    I'll gladly post any more information I find distinctly important about the topic, if I come across it, as should anyone else, of course. However, from the stuff I've read on diesel and cancer for example, I seem to remember that it was considered at least an order of magnitude more dangerous than gasoline exhaust as well. Personally, while there could be health issues with gasoline engines, I'm convinced they're a distinctly lower priority than diesel.

    (and in every case, both are clearly inferior to electricity. )

    KC
    I also like natural gas, as it seems healthier than either diesel or gasoline and I've also heard is better on CO2 than other fuels [hack chemistry warning] because it mostly consists of methane (CH4) which of course has four carbon-hydrogen bonds to release energy, yet only produces one molecule of CO2 per molecule of methane, which is the lowest possible CO2:energy ratio from that family of hydrocarbons.

    The problems usually associated with natural gas are the cost per kilometre and in vehicle design for large capacity fuel tanks. Naturally health is more important, but how committed are we really?

    (and besides, electricity is both healthier and cheaper anyway... )

  8. #8
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    Quote Originally Posted by Scott
    I understand the afterburner technology on many new diesels (that came out only in the current year!) greatly reduces particulate emissions. -> The particulates are trapped in a filter of some kind, and at intervals additional fuel is added to the exhaust to burn the particulates off.
    Close, but you're confusing the control strategies for two different pollutants. The particulate trap uses nitrogen oxides to burn off the material that accumulates. Diesel engines produce significant quantities of NOx (NO and NO2), and NO2 reacts with trapped particulates (primarily carbon), producing N2 and CO2. NO will slowly convert to NO2 when exposed to oxygen, but the particulate trap includes a catalyst to speed this process up to ensure there is sufficient NO2 to keep the trap clean. Particulate traps have been around for a while and are quite effective, but they could only be used on automobiles after the new low sulfur fuel became available.

    Unfortunately, diesel engines produce so much NOx that the particulate trap only can only use about 10% of it to destroy particulates. Getting rid of the rest of NOx in diesel exhaust is much harder. In a gasoline engine the air/fuel ratio is tightly controlled to ensure that the amounts of oxidizing pollutants (NOx) (and excess oxygen) and reducing pollutants (CO, hydrocarbons) are balanced. The catalytic converter then reacts these materials with each other to form N2, H2O and CO2. Diesel engines, however, have low engine-out CO and hydrocarbon emissions and always have excess oxidizer present so there is nothing to react the NOx with. The solution so far has been to add reductant in the form of extra fuel or urea to allow a SCR catalyst to destroy the NOx. A better solution would be to directly decompose the NOx to N2 and O2, but such catalysts are not yet available. Even when they do become available, they may not be able to reduce the NOx enough to meet upcoming standards, although they would significantly reduce the need for reductant.

  9. #9
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    Quote Originally Posted by KC
    Westport Innovations out of Vancouver with Cummins (Westport is partly owned by Cummins) build natural gas engines that operate on essentially modified diesel engine designs. They are used in trucks and buses and I'm surprised that it's technology that's being ignored as an alternative to diesel. I think it's still being 'proved' but hundreds if not thousands of buses with these engines are in place around the world.

    Their web site is something like www.westport.com or .ca. And there's probably other companies doing the same.
    Politics my friend..politics

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    Politics? Both diesel and natural gas are fossil fuels extracted and sold by the same companies.

  11. #11

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    Quote Originally Posted by Scott
    It's a question about marginal benefits. How much marginal benefit does running trolleys provide to the air quality in Edmonton vs. running Diesel busses. At what cost?

    Coal fired power plants produce particulates as well, albeit, it is more economical to install high efficiency scrubbers on projects of that size. I understand the afterburner technology on many new diesels (that came out only in the current year!) greatly reduces particulate emissions. -> The particulates are trapped in a filter of some kind, and at intervals additional fuel is added to the exhaust to burn the particulates off.

    Diesel buses have certain advantages over trolleys. Trolleys have certain advantages over diesels. The main "pollution" advantage is a relocation of pollution - but certainly, additional vehicles and costs are associated with maintaining the lines.

    It is a question about the marginal return on an investment - maybe it is better to distribute the additional funding to something like an initiative to get high pollution vehicles off the road. Even if we didn't mess with 90% of "old vehicles" but just the ones that belch clouds that cloud the rest of us in our vehicles, that would probably have a high return on investment. Perhaps that is a better place for funds.
    Okay, I think I see where you're coming from, and for what it's worth, I think I basically agree with everything you're saying. I won't get into particulate traps much, as Ti48 said it very well, but I'll just add my oversimplification of them: it's like playing "Whack-a-Mole". As soon as one problem gets taken care of, another one always seems to pop up. e.g., no matter their level of effectiveness they also reduce both the fuel efficiency and the cost efficiency of buses using them. Furthermore I'm not saying we shouldn't get them, just that trying to get a diesel engine to beat a gasoline engine is unlikely, and beating an electric motor in Edmonton's context, is impossible. (and that's arguably an understatement.)

    Of course you're right about trolleys partly being a case of moving pollution to another location, and we agree that the coal plant scrubbers are more economic and effective than any vehicle based diesel emissions technology is ever likely to become. However I just want to emphasise that point in particular, and juxtapose it with other initiatives we have in the city to encourage outdoor, non-vehicular activity, particularly but not only downtown. Whether having a beer on a patio, walking down Jasper, or cycling anywhere downtown, bus pollution can greatly affect people.

    (That's all, I don't mean it as a point in contention. I just wanted to emphasise its importance.)

    Finally onto your main point about marginal benefits and costs: I'm a little reluctant to discuss that here in a thread on health, (and I was thinking to open a thread on bus economics when I got around to it) but...

    Basically the overall costs to the taxpayers depend on how we integrated trolleys with fuel carriers (and which fuel they carry). For low density routes, diesel buses can be cheaper overall; but for high density routes, trolleys are in fact already cheaper, including all wire construction, maintenance, and original vehicle purchase costs. I don't have access to all the information I would need to put together exactly how much cheaper, but it just comes down to the fact that while their fixed costs are definitely higher, trolleys' variable costs for fuel and maintenance are definitely lower (assuming we compare contemporaneous equipment, of course.) Thus if we build and maintain one kilometre of wire and run one 40 foot bus with 10 passengers an hour under it, its a very different financial proposition than running, say, an 80 foot bus with 120 people every 15 minutes.

    The other issue with respects to economics is of course revenues, so we need to consider which would appeal more to riders, if either. (I'd really rather save these things for a different thread though, to avoid repeating things too much. But I agree we mustn't ignore any of the issues.)

    By the way, I completely concur with your idea to get high pollution vehicles off the roads. (i.e., ones in poor running condition.)


    glasshead:

    I'm not sure quite what you're referring to, but just in case I appear to have any political ties, I'll renounce them right now. I don't have any political ties whatsoever, and I don't have any financial ties to anything remotely connected to the issue of either buses or fuels. I vigourously support trolleys simply because I vigourously support Edmonton (and the surrounding area.) and I have just become convinced beyond a doubt that the trolley system is wrongly imperilled, and some people in the city are toying with destroying an unrecognised asset. I truly believe removing it would be a mistake on par with any of the greatest mistakes made in Edmonton's history. (like the non-adoption of Namao for the airport, or the variety of factors that led to the abandonment of the downtown core in the first place.)

    Trolleys don't need separate rights of way, and they can move far more people with existing road space than any other technology, bar none. They have fewer health issues than any other technology except walking and cycling. They have fewer traction issues than any other technology, except other electric vehicles. They are overall quieter than any other bus technology, inside and out. And on economics, there are several existing routes where, if regularly used, they would be cheaper than any other motor vehicle technology bar none.

    I just think it's important that more people know those things and consider them.

  12. #12

    Default It's official, diesel fumes affect people's brains...

    Okay, so in addition to triggering heart attacks, diesel fumes (especially the overly abundant particulate that diesel produces) are now being linked to:

    Thickening the blood (this is the same group that found it triggers heart attacks in the thread starter.)

    Causes premature death (due to a variety of factors, including around .1% of Europe annually.)

    Cause childhood cancer and death (not proven, but worth a read)

    Increases Stroke risk (research from a different continent this time.)

    and finally,
    Yes little Nicola, Diesel pollution affects your brain (I don't get who is still volunteering for these studies. It doesn't have any long term conclusions of the effects, but I don't think it will be long before this is the proven link to migraine headaches and mental stress generally.)

    Pollution in Edmonton's streets may be better than downwind of refinery row, but it is already significant. Technology is improving in vehicles with engines, but our population is also growing. I urge anyone who reads this to consider the benefits of electric transit.

  13. #13

    Default

    Quote Originally Posted by JayBee View Post
    Okay, so in addition to triggering heart attacks, diesel fumes (especially the overly abundant particulate that diesel produces) are now being linked to:

    Thickening the blood (this is the same group that found it triggers heart attacks in the thread starter.)

    Causes premature death (due to a variety of factors, including around .1% of Europe annually.)

    Cause childhood cancer and death (not proven, but worth a read)

    Increases Stroke risk (research from a different continent this time.)

    and finally,
    Yes little Nicola, Diesel pollution affects your brain (I don't get who is still volunteering for these studies. It doesn't have any long term conclusions of the effects, but I don't think it will be long before this is the proven link to migraine headaches and mental stress generally.)

    Pollution in Edmonton's streets may be better than downwind of refinery row, but it is already significant. Technology is improving in vehicles with engines, but our population is also growing. I urge anyone who reads this to consider the benefits of electric transit.


    Interesting - incl. idea that photocopying might lead to dementia.

    Alzheimer's 'is linked to diesel engine fumes': Tiny particles emitted could help to form plaques in the brain that cause the disease

    Study suggests vehicle engines could release particles during combustion

    Break pads in cars and trains may also be at fault for degenerative disease

    Study based on brains of 37 people from Manchester and Mexico City

    The researchers suggested that vehicle engines – especially diesels – could release the tiny magnetic particles during the combustion process. They also said that brake pads in cars and locomotives might be at fault.
    Indoor sources could include open fires, stoves and the powders used in photocopier ink.



    http://www.dailymail.co.uk/health/ar...e-disease.html
    Last edited by KC; 20-09-2016 at 02:28 PM.

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