Originally posted by: CycloWizard
I fail to see how you being an ASE certified mechanic qualifies you to tell me about the health effects of a car's exhaust. I've likely done just about everything to a car that you have, and with absolutely no training - nothing but a Chiltons, but it didn't impart any understanding of the chemistry or dynamics of the exhaust. My engineering background has, however. It has taught me that chemicals can be endured at certain concentrations without risk. The safe concentration varies per chemical. The chemicals in cigarettes, such as cyanide, require a ridiculously low concentration to have effects on you. Some of the effects of chemicals are also chronic rather than acute, but that doesn't mean there isn't an effect.
In reality, the volumetric efficiency has very little to do with this conversation. In reality, the conversion of fuel to carbon dioxide and gas has everything to do with it as far as this discussion goes. The two are related, but as far as this discussion goes, you're missing the point, as it isn't the volume of gas that leaves the exhaust that is the problem. The problem is the makeup of that stream. If we had 100% consumption of fuel, then the exit stream would ideally be carbon dioxide and water. Instead, it comes out with various COx and NOx species, since the engine is hardly an ideal reactor. So, if you want to make an argument of the form you're weaving, you need to consider the net output of these harmful species. You would also need to consider their health effects (which are very, very low relative to chemicals in smoke). You would also need to consider dilution effects.
As for the calculation itself, the volume output matters not at all. What matters is the molar/mass output rate of these 'harmful' chemicals. So, you'd need to look at the engine as a reactor instead of a simple airflow unit. You'd need to consider catalytic conversion effects. You'd need to consider chemistry of fuel additives. All of these things you ignore because you don't have the background I do, which is fine. However, I do understand them and am trying to tell you what I know. If you're going to reject it out of hand, then you're closed minded, as I previously stated.
I take no issue with whatdguy said because it's obviously ridiculous. You, on the other hand, are trying to pass yourself off as an authority on the subject when you are not. Since I am (at least relatively speaking), I feel obligated to call you on it. If you're going to try to persuade someone, you should be aware of the relevant considerations before you try to make an argument. I can't fault you for not knowing everything I do, as 99.999% of society does not. However, that doesn't mean I'll sit idly by and watch you spout out things that I know are false. It's what I do, whether you or I like it or not.