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Actually, the soot in diesel exhaust is much more carcinogenic than that of a (well tuned) gas engine. There are various studies, one california based study sh

Actually, the soot in diesel exhaust is much more carcinogenic than that of a (well tuned) gas engine. There are various studies, one california based study showed diesel soot was up to 70% of cancer for californians. Not saying that I want to breath either, but i'd rather suck down a mouthful of gasoline engine exhaust than diesel soot while on my morning bike commute. Edited to add: After reading a bit more, I see your point. I guess there have been new studies since I last read that show that per unit of mass, the volatile organic compounds in gasoline exhaust are more harmful, they just have less volume than diesels. Seems to be about a draw.

simonsarris 16y ago
In the US, yes, but thats a US problem. But diesel in the UK now has 10 ppm sulfur. In the US it used to be higher than 500 ppm, now its regulated to 500ppm for some vehicles and lower for some other classes. Starting in 2014 all US will be 15ppm.
- cullenking 16y ago
  Actually, in the US it was 500ppm in 2007 (LSD), and by the end of 2010 it will all be ULSD (15ppm sufur) for onroad vehicles. 2014 is when the exemptions for some small offroad vehicles and the like are removed. http://en.wikipedia.org/wiki/Ultra-low_sulfur_diesel#United_States http://en.wikipedia.org/wiki/Ultra-low_sulfur_diesel#United_... Also, soot isn't directly related to sulfur in fuels. It's the suit removing mechanisms in newer diesel vehicles that are ruined by sulfur, so newer vehicles can't run fuel with sulfur in it without incurring a large repair bill. An older diesel vehicle that belches out soot will continue to do so, regardless of sulfur content.
JofArnold 16y ago
If I remember when I get back, I'll try to find the article I read about nano-scaled particles from gasoline combustion (I think it focussed on mutagenic properties and in particular the body's inability to move them out of the lungs versus micron-scale which can be expelled more easily). But the VOCs definitely not great. Plus, presumably (I'm guessing), the NOxs from high temp lean combustion in modern gasoline engines are an important factor too?

simonsarris 16y ago

In the US, yes, but thats a US problem. But diesel in the UK now has 10 ppm sulfur. In the US it used to be higher than 500 ppm, now its regulated to 500ppm for some vehicles and lower for some other classes. Starting in 2014 all US will be 15ppm.

cullenking 16y ago
Actually, in the US it was 500ppm in 2007 (LSD), and by the end of 2010 it will all be ULSD (15ppm sufur) for onroad vehicles. 2014 is when the exemptions for some small offroad vehicles and the like are removed. http://en.wikipedia.org/wiki/Ultra-low_sulfur_diesel#United_States http://en.wikipedia.org/wiki/Ultra-low_sulfur_diesel#United_... Also, soot isn't directly related to sulfur in fuels. It's the suit removing mechanisms in newer diesel vehicles that are ruined by sulfur, so newer vehicles can't run fuel with sulfur in it without incurring a large repair bill. An older diesel vehicle that belches out soot will continue to do so, regardless of sulfur content.

JofArnold 16y ago

If I remember when I get back, I'll try to find the article I read about nano-scaled particles from gasoline combustion (I think it focussed on mutagenic properties and in particular the body's inability to move them out of the lungs versus micron-scale which can be expelled more easily). But the VOCs definitely not great. Plus, presumably (I'm guessing), the NOxs from high temp lean combustion in modern gasoline engines are an important factor too?