To those who advocate abolition of the ICE, please don't throw the baby out with the bath water! The problem, gentlemen, is with the liquid hydrocarbon, NOT with the ICE. Use gaseous fuels like hydrogen, methane, or the combination of both, and this problem will be much ameliorated.
Guess who has been advocating Hydrogen and methane ICE all along here in GCC?

@ Rafael

There is some naturally-occurring ultrafine PM produced as SOA from biogenic VOC emissions (mostly alpha-pinenes from conifers; isoprenes from deciduous trees apparently don't produce much SOA).

Actually some level of ambient particles is critical for precipitation (rain, snow, etc.) events to occur (although not necessarily UF). They serve as condensation nuclei (heterogeneous nucleation of water vapor). Without condensation nuclei, homogeneous nucleation would be the only way for WV to condense, and that occurs at about -40 degrees C. Virtually the entire earth would likely be a desert under those conditions.

@dt

You’re correct and I should have been more specific about particle NUMBER emissions being equaled or exceeded by gasoline engines relative to uncontrolled diesel engines under certain common driving conditions.

@joe padula and Roger

CNG has been shown to produce ultrafine PM emissions that generally exceed clean diesel in several bus studies (including CARB which is certainly not a diesel proponent). On top of that, the UF PM from CNG is about 7 times more mutagenic than the UF from clean diesel buses, and CNG produces higher emissions of virtually every other pollutant with the possible exception of NOx, even with an oxidation catalyst. I haven’t seen any studies that looked specifically at light-duty CNG vehicles, but extrapolating the CNG bus studies casts some doubt on those also (at least as being a better option than clean diesel).

IIRC, there was a post here on GCC a while back that mentioned a study that even hydrogen ICEs produce UF PM, apparently from the lube oil that is consumed.

In my opinion, clean diesel is the best option at this time, at least until EVs are ready for prime time.

Carl,
Your assertion that CNG combustion produces higher emissions of virtually every pollutants than clean diesel simply flies on the face of common sense.
CNG combustion, when properly regulated, is the cleanest of all hydrocarbon. The methane molecule is so simple and so easily combusted that the likelyhood of formation of carcinogenic compounds would be nil, unlike long-chain hydrocarbon liquid fuels like diesel fuel, and aromatic compounds in gasoline. In fact, I would seriously question the contention that modern gasoline engines produce just as much but finer particles as diesels, unless the engine is out of tune! A good oxidative catalyst when properly functioning, can burn a substantial number of these fine hydrocarbon particles. The finer they are, the easier to burn them off into CO2 and H2O. The more reactive free radicals they have, the easier it would be to render them inert in the catalytic converter.

Adding H2 to methane (hythane) can further make methane combustion even cleaner. For advanced ICE that does not consume oil, or very little oil, the PM emission from oil combustion would be zero, or nearly so.

References to support your assertion, please.

@ Roger

Here are a few references concerning the CNG vs. clean diesel bus studies:

http://www.osti.gov/bridge/servlets/purl/829623-F0uIqi/native/829623.pdf

http://www.wspa.org/pdfs/fuels_Diesel_Update_Final.pdf

The hydrogen study I mentioned was from memory, which at my age probably isn't very reliable. Anyone else remember that post?

As far as the gasoline vs. diesel ultrafine emissions, please see the University of Minnesota study I referenced in my first post.

Carl thanks for the reasoned analysis backed by substantive research. It's always nice to have factual information trump what's touted as common sense. By the way is this the Hydrogen article of which you speak?

http://www.greencarcongress.com/2007/10/study-lube-oil-.html

A

excerpt from Carl's reference, on the bottom of page 5 of 20:

http://www.wspa.org/pdfs/fuels_Diesel_Update_Final.pdf

"These studies were designed to characterize
emissions for individual heavyduty
vehicles, and thus do not represent
average emissions for the entire
fleet of heavy-duty vehicles. Also, the
CNG and clean diesel technologies are
both extremely low-emitting systems
and therefore challenge the sampling
and analytical methodologies to the
limits of detection."

Carl,
Both CNG engine with oxadative catalyst and diesel with PDF are considered to have extremely low toxic emission near the limit of detection, and hence are considered to be equivalent, due to imprecision in sampling. It would be like splitting hair in saying which one is better than the other.

What more relevant is the high cost of Diesel fuel AND the cost of Diesel DPF over a give period of time in use, in comparison to the much lower energy cost of CNG fuel and the abscence of the very expensive DPF AND of NOx treatment for diesel. CNG engine inherently produces much lower NOx level than Diesel.
CNG wins hands down, no question needs be asked!

@ winnipeg BioD

That's it! Thanks.

@ Roger

I completely agree that both CNG/OC and clean diesel are exceptionally low in emissions. I'm just responding to the numerous comments here on GCC that imply that diesel is the sole source of ambient PM, ultrafine or otherwise.

By the way, according to a NYC bus study (CNG vs. clean diesel), it doesn't appear that CNG has any advantage from a cost perspective over clean diesel either. See http://www1.eere.energy.gov/vehiclesandfuels/pdfs/deer_2003/session5/deer_2003_lowell.pdf

Love to see so much commotion over this issue. May ICE die, that people live. Long live EVs.

Great to see research extensions for other Internal Combustion Vehicles following Prof. Mark Jacobson's E85 pollution study as reported in GCC on April 18, 2007.

Instead of the ICE numbers of particles being quoted here, more knowledge needs to concentrate on victims of pollution...you know...coughing blood & young lungs that can't use the oxygen in the air anymore.

Roger Pham...Do not fear. Only you have talked about political abolition of ICE. Even my comment only refers to 'death to ICE' by economic, not political means. So lets work hard to get electric energy densities way up, charge times way down, renewable electric sources way many & EVs on the road. Then, ICE will die(economically), that people will live. Long live EVs.

Any thoughts on Energy from waste (incinerators) and there nano-particulates. Is it fair to believe that these will contribute fine dust to surrounding areas. We have a local council trying to bring one into our area and we have concerns.

"Posted by: arnold | Jan 20, 2008 7:21:02 PM

I'm curious whether the ultrafine particulate issue would be different for biodiesel. Anyone know?

50 mpg on biodiesel made from non-edible feedstocks is still a decent short to medium-term option while we wait for affordable BEVs. Or at least I hope it is..."

From what I've read in British news is that bio-diesel is better than existing diesel, but not free from Small Particle Pollution or Ultra Fine Particle Pollution. Both cause problems, but the specific problems of the Ultra-fine have been pinpointed in this report. I think more of the cloud like haze that hangs over Disneyland, than normal diesel exhaust with the Ultra-Fine. Small Particle is more what I think of with diesel, and combustion. My personal images of sources may be wrong, but both size particles are bad for health.