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Old 09-24-07, 02:54 PM   #1
randya
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Deadly Diesel Exhaust



Published online: 20 September 2007
Stay in if you're having a bad air day
Studies show diesel smog increases chances of deadly blood clots.
Ewen Callaway
http://www.nature.com/news/2007/0709...070917-10.html

Study after study has shown a connection between smoggy days and an increase in deaths. Now two experiments, one on mice and the other in men, clarify why. Diesel fumes, they find, encourage blood clots that can bring on heart attacks and strokes.

The study in people helps to prove the correlation between heart problems and a city's poor air quality and hints at the role of clotting in this process. And the work in mice exposed to smog suggests that the immune system kick-starts the process.

Together, the two call attention to the dangers of air pollution for people with heart trouble. "The message we're trying to promote is please exercise, it's good for your heart and your health. But if it's a bad [air] day you should think twice," says David Newby, a cardiologist at the University of Edinburgh, UK, who led the clinical study.

Proof Positive

Up to 800,000 people around the world died from causes attributable to air pollution in 2000 alone, according to the World Health Organization — many through heart attacks and stroke.

To add experiment to observation, Newby's team recruited 20 men who had previously had a heart attack. The team exposed half the patients to diesel exhaust made by a Volvo tractor engine — about equivalent to a smoggy day in London — while closely monitoring their condition.

After 2 spells of 15-minutes on an exercise bike, the patients who inhaled the small amounts of soot showed the strain. Less blood made it to the muscular tissue of their heart, and levels of a protein called tPA, which responds to blood clots, were lowered. After the experiment, these factors returned to normal.

"This sort of back-up mechanism [to clotting] is lost when you're exposed to diesel, and therefore it makes a clot form a lot more likely to be successful and a heart attack to occur," says Newby, whose team reports the findings in the New England Journal of Medicine1.

Clot Away

Previous work in hamsters identified excessive blood clotting, or thrombosis, as a culprit. Now a study in mice shows how this happens.

Gökhan Mutlu, a physician at Northwestern University's Feinberg School of Medicine in Chicago, and his colleagues were studying the effects of air pollution in mice when they noticed that animals exposed to dirty air didn't bleed for as long as mice that breathed clean air. The fume-inhaling mice showed higher levels of several proteins linked to blood clotting.

When Mutlu's team eliminated immune cells that are likely to mop up soot particles from the lungs of mice, no clotting problems occurred. The same thing happened in mice that were missing a gene for an immune signalling protein called interleukin-6.

The results suggest that it is the immune response to particles in the lungs that causes inflammation and leads to clots, they report in the Journal of Clinical Investigation2.

"These two studies are pretty nicely complementary," says Mutlu, referring to his work and Newby's clinical study.

Cleaner Air

The two studies are convincing, but there could be other explanations for how air pollution causes heart attacks, says Benoit Nemery, a toxicologist at the Catholic University of Leuven, Belgium. He has shown that tiny soot particles enter the bloodstream where they may affect the heart directly, rather than via an immune response in the lung.

Nemery agrees that people with heart problems shouldn't run marathons when the air is poor, but he sees a better solution than stopping the exercise: "I don't think you should blame the victims — that they should change they their way of life. What we should aim for is to make the pollution go down."
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Old 09-24-07, 03:44 PM   #2
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I always say, regardless of which side of Global Warming you're on, why does science have to keep telling us how bad this kind of stuff is for our well being for anyone to care?
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Old 09-24-07, 04:33 PM   #3
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diesel fuel and diesel engines got a pass on stricter pollution controls in the 70s and 80s because of the trucking industry's and truck manufacturers' lobbying strength.
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Old 09-24-07, 04:49 PM   #4
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diesel fuel and diesel engines got a pass on stricter pollution controls in the 70s and 80s because of the trucking industry's and truck manufacturers' lobbying strength.
In general burning fossil fuels is bad for air quality and the general public's health, alas like most of our power comes from burning coal still. :roll:
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Old 09-24-07, 05:08 PM   #5
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it's the street level exhaust that gets you though; I at least partially attribute my asthma to many years spent cycling in an urban environment...

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Old 09-24-07, 05:56 PM   #6
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it's the street level exhaust that gets you though; I at least partially attribute my asthma to many years spent cycling in an urban environment...

My asthma was much worse when I lived in a small town in the mountains (read: VERY low air pollution) and didn't ride as much. I've been riding in the Denver area for 4 years now (riding more than I did in the lower pollution air) and I haven't had an asthma attack in months. The ones I have had were less severe.

I think there's a lot more at play than 'just' air pollution....
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Old 09-24-07, 06:40 PM   #7
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Check this product out:

The Respro Sportsta mask combines HEPA-type filtration performance associated with sub-micron pollutants such as pollen and other irritant dusts, with a lightweight Neotex aerated mask. The Respro mask offers maximum ventilation without sacrificing filtration and to maximize rider performance, state of the art Powa valves are a standard feature and a must for all who ride to their limits.
The Respro mask conforms to European Standard EN149FFP1(S) for solid aerosol particles and is usable in all outdoor sports pursuits requiring respiratory protection.

Usable for sports activities, pollution avoidance, and as a cold weather mask
Filters out sub-micron particulates, including:
pollen dust
irritant dusts
clay dust
black smoke
exhaust emissions
diesel particulates
Rapid airflow valve system offers low breathing resistance
Velcro fastening fits without fuss and is fully adjustable
Made from neoprene - durable and washable
Replaceable filter lasts approximately 150 hours



http://www.allergybegone.com/confacmaslar.html
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Old 09-25-07, 08:20 AM   #8
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I always say, regardless of which side of Global Warming you're on, why does science have to keep telling us how bad this kind of stuff is for our well being for anyone to care?
This is why I've always felt that the environmental movement focus on global warming was a mistake. If "they" (the larger, more influential voices in the movement) had pushed the easily quantifiable health concerns from pollution rather than the real but harder to demonstrate with hard facts GW issues they would have been much harder to ignore. Plus there would have been the added bonus of social justice (incinerators proximal to low income areas, etc) but I guess it wasn't as sexy as global warming.
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Old 09-26-07, 05:30 AM   #9
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Anyone ever have a diesel pickup truck slow way down and then floor it as they go by purposely leaving you in a cloud of black diesel smoke?

I've had that happen twice.
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Old 09-26-07, 09:59 AM   #10
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I was in Cuba earlier this month, and while I did not bring a bicycle, I was amazed at how everyone on the road yielded to other road users based on their size/vulnerability, from pedestrians > cyclists > motorcyclists > cars, etc.

The big vehicles slowed down and waited behind cyclists until it was safe for them to pass, in the city or on intercity roads.

The only major downside to riding a bike in Cuba is the thick black diesel smoke trails that those big vehicles spew out, most often right in the face of cyclists as they get passed.
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Old 09-30-07, 06:08 AM   #11
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My primary vehicle is my bicycle, but when I do need to use a motorized vehicle, I drive a VW Jetta wagon - diesel, which runs on biodiesel. I get 48 mpg and although it does put out more particulates than a clean gasoline engine, I believe that on balance, a modern clean burning diesel engine, running on biodiesel is an environmentally sensitive solution.
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Old 09-30-07, 07:53 AM   #12
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it's the street level exhaust that gets you though; I at least partially attribute my asthma to many years spent cycling in an urban environment...

One of the benefits i don't live in an urban environment
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