health impacts of diesel emissions

[feraldisco]

It's not a particularly new article, but the information is still pretty current - particularly the interesting bit about the new particulate filters not cutting out the smallest and most harmful particles (and you'd think that a filter that was able to cut these out would be rather restrictive).

The truth about diesel (http://smh.drive.com.au/owning-tips/the-truth-about-diesel-20090806-eaoj.html)

and no...this isn't a baiting exercise as I drive a Td5...but I'm also glad I don't live in a high traffic area...

[Dougal]

A 3 year old article citing an even older US article based on estimations by unnamed air quality experts.

Sounds a bit loose to me. Euro emissions standards have tightened since that article was written, but it seems equally concerned with pre-euro vehicles which will continue to decline in numbers.
Are the authors completely unconcerned about the unclean petrol engines on the road as well?
Modern diesels run an exhaust so clean there is no soot inside the pipes. Very few petrols can meet that.

What I find particularly interesting is how the US claims in 2002 that diesel exhaust is so particularly harmful, when there are virtually no light diesel vehicles on their roads. Do their large pickup trucks and linehaul freighters make up for the 4 million miles that commuters drive in petrol vehicles in LA every day?

Colour me sceptical, but what hand do the US automakers have in lobbying to keep diesels which they don't have out of their country?

[3toes]

Reason there are so few diesel cars on the road in USA is their very tough clean air exhaust rules. These are far tougher than the relatively lax European rules. Contrary to what some in the media may want you to believe. Also these rules have been tightened progressively over the last 30 years with targets set on a rolling 10 year basis. Japan also has tougher emission rules than Europe whose rules cover CO2 leaving NO2 and particles out. All this is due to politics. USA has / had domestic access to light crude which makes petrol. Europe had only small oil resources so went harder for diesel to keep import costs down. Also Europe was never keen on this sort of thing rather believing they could tax drivers off the road.








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[Dougal]

Reason there are so few diesel cars on the road in USA is their very tough clean air exhaust rules.

So you think it has absolutely nothing to do with the US producing the worlds worst diesel engines in the 80's (converted petrols) which have forever poisoned the US public's perception of diesel?
Car makers like VW have never had a problem making and selling diesel cars which meet the US emissions standards, they've been sold in the US from the mid 80's and are still sold there now.

Does it also have nothing to do with the US car makers lobbying government rule-makers for rules which help them sell more cars and keep more US citizens employed?



These are far tougher than the relatively lax European rules. Contrary to what some in the media may want you to believe. Also these rules have been tightened progressively over the last 30 years with targets set on a rolling 10 year basis. Japan also has tougher emission rules than Europe whose rules cover CO2 leaving NO2 and particles out. All this is due to politics. USA has / had domestic access to light crude which makes petrol. Europe had only small oil resources so went harder for diesel to keep import costs down. Also Europe was never keen on this sort of thing rather believing they could tax drivers off the road.

European emissions laws are now very similar to US emissions laws. The reasons they target different emissions is due to the problems each part of the world had which needed to be solved.
The US has a massive problem with NOx (that brown crap that covers LA) and smog, hence they regulate NOx and hydrocarbon emissions more tightly.

[rick130]

Also, the US for years refused to legislate ULSD.

They only dropped to <50PPM sulphur diesel two years ago, (we are <10PPM in Australia) amid cries of impending doom.
Europe went to <50PPM diesel something like 15 years ago.

The reason we didn't get the efficient little common rail and unit injector Euro diesels for a long time was because our diesel was too dirty too.

[blackbuttdisco]

We drove a diesel motorhome for 10 months in UK. It was clean when we bought it and it had its first wash 10,000miles later.(we did 22,000miles all up). There was no diesel soot stain down the side from the exhaust, so to me, it had a very clean exhaust. (Which is more than could be said about my turbo 2A. )Had it up to 80mph before I slowed down and there was still more to go. It would do 35mpg on cruise control on the motorways at 60mph. UK may have gone metric but the distances are still in miles and fuel is sold by the litre.

[3toes]

Car makers like VW have never had a problem making and selling diesel cars which meet the US emissions standards, they've been sold in the US from the mid 80's and are still sold there now.


Of course these diesels were only sold in a few mid US states as they could not meet the emmissions standards required of California and North East USA. As they could not meet the increasingly tough rules VW withdrew diesel in the late eighties and only re introduced in last few years. Due to emissions being too high even these new ones are illegal to buy new or bring in to California as a used car buy from another state.

You have to remember USA has 2 levels of emissions rules National and State Government. The latter of which are based on winning votes by being tougher than the National Regs while following those of the future years regs set nationally just sooner.

[Dougal]

Of course these diesels were only sold in a few mid US states as they could not meet the emmissions standards required of California and North East USA. As they could not meet the increasingly tough rules VW withdrew diesel in the late eighties and only re introduced in last few years. Due to emissions being too high even these new ones are illegal to buy new or bring in to California as a used car buy from another state.

You have to remember USA has 2 levels of emissions rules National and State Government. The latter of which are based on winning votes by being tougher than the National Regs while following those of the future years regs set nationally just sooner.

That's why they call it Kalifornia. It's not about emissions levels in CA either, it's about them being diesel. I suspect even diesels exceeding future petrol emissions levels would still be decried as being dirty by CARB.
I wonder if the people making these laws had their perceptions of diesel formed by watching a 350ci oldsmobile diesel smoking it's way back to the dealership to have it's head bolts replaced again.


I find it interesting that LA has such a NOx and smog problem with essentially no light diesel vehicles, yet diesel vehicles are still the cause of all their problems. I've even read one website proclaim that most of the smog over US cities is actually generated overseas and just happens to collect there. Apparently cleaning up the Tuk-tuk's in Bangkok will reduce smog in LA.

I think it's simply easier to whip industry and trucking companies than risk upsetting the people who vote for you by making them fix their cars.

BTW it's not illegal to take a diesel car into CA, you just can't register it there unless it's over something like 8,500lb gross. There are plenty of people in california driving diesel vehicles on loan from relatives in other states.
So their rules push law abiding people who want diesel vehicles into driving cummins powered pickup trucks when all they really want is a diesel car.

[rick130]

Isn't Cali advocating/proposing zero envisions in the next couple of years ?
Effectively banning new fossil fuelled internal combustion engines ?

I read one report on oil/fuel usage a year or so back that stated that California uses more barrels of crude per annum than either China or India, even with both countries massive industrial expansion :eek:

[Dougal]

Isn't Cali advocating/proposing zero envisions in the next couple of years ?
Effectively banning new fossil fuelled internal combustion engines ?

I read one report on oil/fuel usage a year or so back that stated that California uses more barrels of crude per annum than either China or India, even with both countries massive industrial expansion :eek:

I think their original deadline for zero emission vehicles (i.e. electric powered by coal power plants) has flown by years ago. That was to sell cars in Cali you needed to have zero emission cars on the showroom floor.
Didn't fly. Turns out you can't mine hydrogen either.:angel:

[MEANZ06]

^---- deisel truck in cali... :angel:

they are putting new sanctions on the large trucks soon. it will cost each of them several 1000's to upgrade. i would expect that the $'s will trickle down to the consumer... :(

[feraldisco]

We drove a diesel motorhome for 10 months in UK. It was clean when we bought it and it had its first wash 10,000miles later.(we did 22,000miles all up). There was no diesel soot stain down the side from the exhaust, so to me, it had a very clean exhaust. (Which is more than could be said about my turbo 2A. )

One of the main points about my original post was that the problem of large highly visible ("soot") particles has largely been solved, but it seems that it's the very small particles that may be the greatest health threat and presumably difficult to completely eliminate from emissions.

[isuzurover]

One of the main points about my original post was that the problem of large highly visible ("soot") particles has largely been solved, but it seems that it's the very small particles that may be the greatest health threat and presumably difficult to completely eliminate from emissions.


This is a very complex issue and I don't really have time to type a complete answer.

Diesel Partiulate Matter (DPM) has been found to be harmful and/or carcinogenic. DPM is also like activated carbon, and can have a number of molecules like PAHs adsorbed in significant quantities.

DPM particles start off at about 1 nm (nm = nanometre = 1x10-9m) in the engine, then grow as spheres until they reach 10-30nm. By this stage they have then passed out of the hot-zone of the engine (~>500oC) and start forming fractal-like agglomerates - i.e. - primary particle size is ~10-30nm, agglomerate size has an aerodynamic diameter of 200-400nm.

You seem to be thinking that DPFs (diesel particulate filters) work like sieves. This is not true. Particles at the smaller end are highly diffusive and therefore easily removed. Particles at the larger end are harder to remove and more readily inhaled.

However - higher injection pressures and hotter engines/exhausts produce a smaller average particle size - so modern engines tend to produce smaller particles but lower overall mass.

Wrt health effects, most/all studies have found that surface area is much more important than mass.

The Euro IV emissions standard have significantly reduced DPM emissions - in terms of mass - and I am sure surface area as well.

Incidentally, new, DI petrol engine technology is also starting to have issues with PM formation.

[rick130]

[snip]

Incidentally, new, DI petrol engine technology is also starting to have issues with PM formation.

Interesting.

Getting OT for a sec, DI petrol engines are also having significant fuel dilution issues with their lubricant too, and most all oils can't cope.

From what I've been told from a US source, oil change intervals have to be pulled back significantly from what the Euro manufacturers were heading towards if long term engine life is to be achieved.

[SwedishBloke]

PM 10 particles, particles equal or smaller than 10 micrometer, is a big health concern. The small size of them makes it possible for them get through the bodies protection system of mucous membranes in the air ways and get straight into the lungs and other critical body systems. If you live in a densely populated urban area close to a road with high traffic the chances of you getting health problems related to particles, cancer, cardiac arrest etc, increases with like 50 percent.

Particles from exhausts are just one of the issues. Other sources of particles are the tare of break discs, tare of the road surface caused by heavy vehicles, traffic lights (due to people breaking and accelerating which increases the previous factors), buildings blocking the wind that otherwise would have spread the particles over a larger area etc.


So we won't escape all of the problems with particles by simply getting rid of emissions from the combustion engine, which will take some time. Better planning of how roads and cities are built is a major factor.

[3toes]

To give this a perspective people might be able to better relate to diesel particles are like asbestos fibres to the lungs. This is a health issue which has been well known for a couple of decades. The problem becomes worse the more are using diesel power. There is going to be a big class action law suit over this brought by the people suffering life threatening health problems against - car / truck manufacturers, engine manufacturers, transport operators, government and oil companies who ever has the deepest pockets at the time.

Politicians in Europe prefer to ignore the issue while in the USA it is taken seriously. Neither seems to be able to do much that has real impact on the street. Targeting only some classes of transport or users of diesel is never going to be effective however is the only realistic answer. As yet no one has found a way to effectively remove them from the exhaust.

[Dougal]

How do petrol and lpg engines fare for fine particulate matter? I recall reading something years ago that LPG engines (obiously pre catalyst times) were the worst for fine particulates.

I also found a good article comparing particulates of used vehicles of different ages in the US. They tested good vehicles and ones on their last legs. Interestingly there wasn't a good correlation between vehicles that visibly smoked and particulates.
I tried to find the article the other day but couldn't. I'll keep looking.

[3toes]

Not sure about petrol and gas particles against diesel. A quick look did not produce any results in Google. What I did find was this from the New South Wales department of Environment, Climate change and Water.

"Diesel vehicles make up around 8 per cent of all motor vehicles in the NSW Greater Metropolitan Region but are responsible for over 60 per cent of the particle emissions from road transport."

Ozone and particles - Department of Environment, Climate Change and Water NSW (http://www.cleartheair.nsw.gov.au/science_and_research/science/ozone_and_particles/rate/1.aspx)

Interesting to note that according to their figures 45% of the heavy rigid trucks on the road in Sydney are pre 1990 models. As these are 2008 figures those are nearly 20 years old. Careful drivers / very good maintenance or tight operators to keep such ancient trucks working commercially. Only vague % given no actual compareable numbers provided though.

[rick130]

[snip]

Interesting to note that according to their figures 45% of the heavy rigid trucks on the road in Sydney are pre 1990 models. As these are 2008 figures those are nearly 20 years old. Careful drivers / very good maintenance or tight operators to keep such ancient trucks working commercially. Only vague % given no actual compareable numbers provided though.

Naa, they're Japanese trucks, not Euro, and mostly Isuzu NPR's :D

[Dougal]

What is the deal with particulates from petrol engines running rich?
Most petrols run well rich of stoich near full throttle, the unburnt fuel either has to come out as charred particles or sit in the cat converter until enough excess air can burn it off.

But on a sustained WOT event, what happens? There's no lift off with fuel cut to burn them clean.
I know the clowns with venting BOV's on turbo petrol cars end up with the back of the car covered in soot that would put a diesel to shame.

[Dougal]

Politicians in Europe prefer to ignore the issue while in the USA it is taken seriously.

To put things into perspective, the US considers PVC insulation on electrical cords to be a cancer risk. It's funny how much emphasis they can put on things they touch when you look at what they eat.

[JohnF]

Not sure about petrol and gas particles against diesel. A quick look did not produce any results in Google. What I did find was this from the New South Wales department of Environment, Climate change and Water.

"Diesel vehicles make up around 8 per cent of all motor vehicles in the NSW Greater Metropolitan Region but are responsible for over 60 per cent of the particle emissions from road transport."

Ozone and particles - Department of Environment, Climate Change and Water NSW (http://www.cleartheair.nsw.gov.au/science_and_research/science/ozone_and_particles/rate/1.aspx)

Interesting to note that according to their figures 45% of the heavy rigid trucks on the road in Sydney are pre 1990 models. As these are 2008 figures those are nearly 20 years old. Careful drivers / very good maintenance or tight operators to keep such ancient trucks working commercially. Only vague % given no actual compareable numbers provided though.

Sme of the trucks do a the best part of million Kilometers per year so they are going to produce more polution per deisel motor due to the large amount of use the truck/motor gets. Most cars [Taxi's, etc. excepted] are driven and then parked all day, while the trucks are kept running around all day.

Make rail more competative and so remove the need for many of the trucks.
Years ago we had freight carried around Sydney on electric Railway trains [Electric Parcel vans, or what ever they were called], but these were stopped, and everything instead went onto the trucks.

[Dougal]

Sme of the trucks do a the best part of million Kilometers per year so they are going to produce more polution per deisel motor due to the large amount of use the truck/motor gets. Most cars [Taxi's, etc. excepted] are driven and then parked all day, while the trucks are kept running around all day.

Trucks have got to be on the highway most of the time to rack up big numbers and the trucks that do those big numbers are worn out and replaced quite often. I actually wonder where they all go.

The rigid trucks they're talking about in Sydney will be doing things like delivering bread, tow-trucks etc and most would only do a few hundred km in a working day. I'm still surprised at their claimed numbers, when I was in Sydney in 2000 I didn't think 45% of the trucks then were pre 1990, let alone 10 years later.

[PhilipA]

I didn't think 45% of the trucks then were pre 1990, let alone 10 years later.

Nah , Its the buses. I remember a story a couple of years ago that many were 30years old.
Regards Philip A


"The standard life of a bus is approximately 25 years, and as they reach their use-by-date
they need to be replaced, he said. Quote from Sydney buses press release, also stated average age is 12years.

[jasonedu]

i think the science is pretty clear on this one. diesel emissions are a problem.

also quick check on http://www.greenvehicleguide.gov.au shows no diesels in the top 50. I think that says a lot.

[Dougal]

Nah , Its the buses. I remember a story a couple of years ago that many were 30years old.
Regards Philip A

That does make sense. However the buses in NZ that are 30 years old seem to be running engines that are 10-15 years old. I wonder if the statisticians took that into account.