Diesel Fumes Cause Cancer

[Dragonfly]

I think that with modern filtering and catalytic conversion and EGR even old classic diesels can be made cleaner. As someone mentioned, their particles are larger, thus easier to catch.

[strad]

I wish that were true but it's not the carbon,,the black smoke is relatively safe compared to the invisible stuff.

[Dragonfly]

One thing I've noticed about modern common rail diesels is that there is a very definite smell of NO2 from their exhaust. It's a very specific smell and I know it from the times I used nitric acid to etch PCB's.

[xxChrisxx]

To be fair, this is all irrelevent. The reason you are up in arms strad is for two reasons:

1. Cancer is a scary buzzword.
2. You don't understand relative risk.

It is given the same relative risk as passive smoking. About 25%ish relative risk increase (sources place the relative increase from 20-30%, so I took the average) on non smokers. In the US non smokers account for about 20% of cases, 80% being smokers. Per year the incidence of about 70 cases of lung cancer per 100,000.

Non smokers: 70*.2 /100000 = 14/100,000.
Absolute increase due to diesel exhausts, assuming the same relative risk as passive smoking.
14*1.25 = 17.5 / 100,000.
So overall an increase of 3.5 people per 100,000 in a given year will develop cancer as a result of diesel fumes.

In the grand scheme of things this isn't really a large risk.

Notes:
This is not a lifetime risk.
Risk factor is highly dependent on concentration and exposure.
This is not terminal cases, only incidence.

This is obviously a very wooly bringing together of many different sources of information, the numbers vary by a fair margin depending on study. As I am not inclined to perform a more rigourous analysis the exact numbers should be taken with a pinch of salt. The orders of magnitude should be about right though.


The fact is exhaust gases are full of nasty, nasty ---. And things that will kill you much quicker than waiting to get cancer.
CO, NO2 for starters.

Food for thought:
Considering that the whole world is universally complaining about fuel prices (and an increasingly difficult production), how you do propose you replace all the diesel engines? What with? Who's going to pay? Compare this with the negligable increase in risk of cancer.

Also please note that new petrol engines that are running direct injection also produce PM, but this is needed to reach efficiency targets. So do you wish to ban the petrol engine too?

http://www.ncbi.nlm.nih.gov/pmc/article ... =pmcentrez
Study of PM of a smoldering cig vs a 2L idling diesel engine.

[Tommy Cookers]

The fact is exhaust gases are full of nasty, nasty ---. And things that will kill you much quicker than waiting to get cancer.
CO, NO2 for starters.



Also please note that new petrol engines that are running direct injection also produce PM, but this is needed to reach efficiency targets. So do you wish to ban the petrol engine too?

Surely no 4 stroke car engine made since about 1970 (at normal temperature) has been able to produce a lethal level of CO ? (or NOx) ?

Today's petrol engines with DI presumably have protracted injection to minimise NOx production (so avoiding the use of(wasteful) stoichiometric mixtures otherwise needed to allow catalytic reduction of NOx).
I can believe that could produce particulates with the mixture needs of a cold engine, but surely normal running wouldn't produce them ?
Do they have a trap as with diesels ? , or are levels low enough to avoid this ?

[xxChrisxx]

Surely no 4 stroke car engine made since about 1970 (at normal temperature) has been able to produce a lethal level of CO ? (or NOx) ?

Any engine can produce a lethal concentration of CO or indeed anything it kicks out. This is the whole point, in what conditions are you taking the test?

Sit in a closed garage with a pipe from the exhaust into the car window, you will be overcome fairly quickly.
Sat with the car on the drive and a nice cool ventilating breeze. You'll be fine.

So the risk lies with someone who's sucking on exhaust pipes all day - the build up of CO in the blood stream can cause real problems. A fella I know who build comp cars acutally had this, it gives symptoms that can be misdiagnosed as MS.

Someone on the street, occasionally getting a wiff of rich exhaust, will be fine.

Today's petrol engines with DI presumably have protracted injection to minimise NOx production (so avoiding the use of(wasteful) stoichiometric mixtures otherwise needed to allow catalytic reduction of NOx).
I can believe that could produce particulates with the mixture needs of a cold engine, but surely normal running wouldn't produce them ?
Do they have a trap as with diesels ? , or are levels low enough to avoid this ?

They work pretty much the same way the diesels do. EURO V and VI engines have the same emissions standard for both diesel and petrol.

[Tommy Cookers]

Of course if you have a rich mixture your engine is a carbon monoxide generator (petrol worse than diesel). People who operate modified (terrestrial} vehicles and standard piston-engined aircraft should know this. CO detectors are standard in even light aircraft.
It has been said that many suicide attempts (via exhaust poisoning) have failed because reasonably modern cars aren't toxic enough (of course if cold and getting a rich mixture they would stil be toxic, that's what I said).
Long before catalysts in the UK the biggest manufacturer ran his whole product range in the Albert Hall with the press present. No-one died.

Diesel fuel is viscous 'blobby' high boiling point stuff that is always going to be difficult to combust fully as quickly as needed in car size engines (real diesels run at 30 - 50 rpm typically). That's why they have spent the last 80 years steadily raising the injection pressure.

Petrol is the opposite, only in quench areas is it reluctant to burn.
Yes, standards are common, but I've not yet heard of a particulate trap in a petrol engine.

[xxChrisxx]

Long before catalysts in the UK the biggest manufacturer ran his whole product range in the Albert Hall with the press present. No-one died.

Which in a way, demonstrates how silly it is panicing about exhaust fumes increasing your risk of death when you are in the open air.

Petrol is the opposite, only in quench areas is it reluctant to burn.
Yes, standards are common, but I've not yet heard of a particulate trap in a petrol engine.

To be fair, beyond GDI uses similar emission control techniques to TDI, I'd like to be more insightful, but I've kind of reached the limit of my knowledge on this subject.

Regarding GPF: Don't think they have them on EURO V, but most likely will on VI. As that's not due for a couple of years, it's not surprising you haven't heard of one.
http://ec.europa.eu/energy/oil/studies/ ... ofuels.pdf
See technology roadmap Fig 71. Sorry it's not more detailed, just shows it's in the pipeline.

[strad]

. You don't understand relative risk.

Are you trying to be a condesending jerk, or is that just the way you talk?
If you think by this time in my life I don't understand "relitive risk" you're nutz.
I figure I probably with my life experiences know more about risk...relitive and otherwise than most.
Just so you know, I'm the one that laughs when they say something increases your risk 100%..since if only 1 in 10,000 gets something and a 100% increase means 2 in 10,000.

[cheapracer]

You guys do understand they are talking about exhaust fumes.
This strikes home to me for a couple of reasons. Not the least of which is that I work in a world of diesel exhaust fumes.

So let me get this clear, you are aware of the dangers of diesel smoke yet you continue to work in it?

Respectfully, if you contract cancer you won't have contracted it from diesel fumes, you will have contracted it from lack of courage of your own convictions.

[strad]

[xxChrisxx]

You guys do understand they are talking about exhaust fumes.

Pot. Kettle. Black.

If you understand it, why are you worried about something thats low risk compared to other factors in your life?

You've still not answered what you would practically do about it. Don't like it? suggest an alternative that is credible, dont just moan.

[strad]

At 64 there ain't a lot I can do to change the roll of these dice. You know not of what you speak.
It was you, and the future yous I was concerned about and for that I get ridicule?
You guys are the engineers and the ones that seem to think you have all the answers, so come up with something that doesn't include breathing carcinogenic fumes as a by-product. Hell take it a step further, pick up the challenge to find something better than any internal combustion engine.

[xxChrisxx]

It was you, and the future yous I was concerned about and for that I get ridicule?

Robust questioning of your reasoning is not ridicule. You can only claim it to be ridicule because you haven't really prodivded a satisfactory justification for being so worried about it. The irony is we aren't worried about it, because everything has some sort of risk attached to it.

Your response to this article is based on an emotional resposne and not logical reasoning. If it is based on logic, you should be able to state the reasoning behind your position.

You guys are the engineers and the ones that seem to think you have all the answers, so come up with something that doesn't include breathing carcinogenic fumes as a by-product. Hell take it a step further, pick up the challenge to find something better than any internal combustion engine.

This is dismissive and shows an immense lack of respect for both engineers and the task at hand.
It's like one saying that doctors should 'simply cure cancer', whilst implicity saying that tthe only reason they haven't done it yet is becuase they are lazy bastards.

Just as an immense amount of resource is going into finding a cure for cancer, an immense amount of resource is going into making commercially viable green technology.

[strad]

I've kind of reached the limit of my knowledge on this subject.

Leave it at that Chris