Clean diesel may worsen pollution by increasing emission of nanoparticles.

[Walter]

Masaru Sagai: 'Clean' diesel cars may worsen air pollution
http://www.asahi.com/english/Herald-...812020050.html

...incomplete combustion is unavoidable with diesel engines, and could be a fatal defect. The high-pressurized fuel injection systems improved combustion efficiency of diesel engines. As a result, PMs (particulate matter) are released in the form of a fine mist and black fumes have seemingly disappeared. In exchange, however, the level of invisible ultra-fine nano-particles of less than 0.1 micrometer in diameter rose more than several tens of thousands of times. A micrometer is one-millionth of a meter. In short, the particles only became finer and invisible to the naked eye.

It is known that PMs measuring several micrometers can enter the respiratory system and trigger illnesses such as asthma. But nano-particles pass through the respiratory system and enter blood vessels. Furthermore, recent animal tests have proved that they even reach circulatory organs including the heart, as well as the brain, nerve and reproductive systems.
...
Since last year, the Environment Ministry has been studying to establish new environmental standards for PM2.5. But the work is making slow progress and the spread of clean diesel cars will not encourage the government to introduce new regulations.

Since I have asthma, this really concerns me. Does anybody have further information or opinions on this?

[seftonm]

We need to start looking at the emissions of smaller particulates than PM10. PM2.5 and PM0.1 are both probably worth looking at, and until that happens, DPF's are just trading the emissions of a regulated particulate size for emissions of an unregulated particulate size. Gasoline engines don't make much around 10 micrometers, but can be as bad as diesels in the PM2.5 and PM0.1 range.

[Chuck]

If true, this is bad news!

Dan's son in Houston has been treated for asthma. Turns out Houston is the asthma capital of the US. This may be an extra reason to resent diesel-clanging doolies with cowboys that are all hat - no cattle....plenty of them in Houston and D/FW.

[RedRoo89]

A whole lotta diesels around here too. About 50% of them don't even have hitch recievers. 75% of the ones that do have obviously never been used.

[PaleMelanesian]

Originally Posted by Delta Flyer

If true, this is bad news!

Dan's son in Houston has been treated for asthma. Turns out Houston is the asthma capital of the US. This may be an extra reason to resent diesel-clanging doolies with cowboys that are all hat - no cattle....plenty of them in Houston and D/FW.

That and all the Houston-area refineries needed to support the guzzlers, both here and across the country. Houston-refined fuel goes a lot of places...

[The Fridge]

Originally Posted by seftonm

We need to start looking at the emissions of smaller particulates than PM10. PM2.5 and PM0.1 are both probably worth looking at, and until that happens, DPF's are just trading the emissions of a regulated particulate size for emissions of an unregulated particulate size. Gasoline engines don't make much around 10 micrometers, but can be as bad as diesels in the PM2.5 and PM0.1 range.

Well that sucks!
I did a quick google and PM0.1 and smaller are referred to as "ultrafine" particles and the smallest of them are called "nanoparticles". It seems that effects of these smaller particle sizes hasn't been researched as much so naturally regulation will lag behind...

[wxman]

Not sure what country the author of the linked article is from (Japan?), but it doesn't appear it's applicable to the U.S./Canada, at least not the latest clean diesel versions.

All diesel vehicles (cars, HD trucks, SUVs, pickups) manufactured since January 2007 have come OEM-equipped with diesel particulate filters (DPF). DPF has been shown to be extremely effective across the entire particle size distribution.

Several studies have actually shown that DPF reduces particle numbers below ambient (e.g., Färnlund et al., "Emissions of Ultrafine Particles from Different Types of Light Duty Vehicles." Swedish National Road Administration; Environmental and Health Impact From Modern Cars, Ecotraffic (Sweden); John Storey et al., ORNL, "Comparison of Direct Exposure of Human Lung Cells to Modern Engine Exhaust Particles." Proceedings of the 9th Annual DEER Conference). One even shows PM number emissions below that of filtered dilution air (http://www.dieselnet.com/papers/0209czerwinski/).

Even CARB has acknowledge that cars equipped with DPF have lower PM emissions than typical modern gasoline cars (http://findarticles.com/p/articles/m..._7/ai_99232199).

I would also take issue with the assumption that gas vehicles don't produce much ultrafine PM. At least one study shows gas vehicles under some common driving conditions (high speed/load, cold ambient temperatures) produce utrafine PM that can approach or even exceed uncontrolled diesel engines (http://www.osti.gov/bridge/servlets/...ive/829821.pdf).

[RedRoo89]

wxman, I'm very happy to hear all of this. Subaru may be releasing a diesel, so if they do I won't feel bad about driving it.

[phoebeisis]

I think 10 microns or less is the size of particle that can make it down the smallest airways all the way to the alveoli. This is roughly the size of a red cell.

I had no idea that we-in the USA- don't filter out these small particles. If we do- how do we do it? I mechanical filter that fine would have to add a lot of back pressure wouldn't it? Maybe the filters charge theses particles and pull them via the charge to a charged plate.I think industrial stack scrubbers work like this.
Charlie

[Walter]

Originally Posted by wxman

Not sure what country the author of the linked article is from (Japan?), but it doesn't appear it's applicable to the U.S./Canada, at least not the latest clean diesel versions.

All diesel vehicles (cars, HD trucks, SUVs, pickups) manufactured since January 2007 have come OEM-equipped with diesel particulate filters (DPF). DPF has been shown to be extremely effective across the entire particle size distribution.

...

I would also take issue with the assumption that gas vehicles don't produce much ultrafine PM.
...
(http://www.osti.gov/bridge/servlets/...ive/829821.pdf).

Yes, the author is from Japan.
Thanks for the interesting links; I'll read them after Xmas.

Welcome to cleanmpg, wxman!!!
--Walter