Volvo S40 vs. Prius

Well the S40 is a PZEV/SULEV (that's US speak for low emissions) here depending on where you buy it. It's entirely possible that it's going to beat the Prius in some categories and not in others.

 

We are talking about very low quantities here. In addition CO is very unstable and will try to become CO2 if oxygen is present. That is why CO IN CLOSED SPACES is considered dangerous.

 

Actually, the reason CO is dangerous is because CO has a high affinity for the FE at the center of the hemoglobin molecule. Basically, once a CO has glommed on oxygens are excluded or kicked off if they're already there. Once that happens you blood carries decresing amounts of O2 around to where it's needed and you are slowly asphixiated. CO2 in high concentrations is also dangerous.

 

Oh, and CO is bad because in the lower atmosphere it causes the production of Ozone (O3). Ozone is a pollutant in the lower atmosphere. It's bad fer yer lungs. The NOx compounds are the other guys that create Ozone in the lower atmosphere. Unfortunately, when the NOx compounds get into the upper atmosphere they destroy Ozone. Chemistry is against us (or at least the idea of buring fossil fuels).

 

Good reponses and to the point. But the choice is between the Volvo S40 and the Prius. I'll take the Prius for emissions even though the Volvo is a fine car (my other car is a Volvo XC 70). Could you add a sense of proportion to the detail you provide? How big is the problem which you describe?