CO is carbon monoxide and CO2 is carbon dioxide. CO is poisionous in that it will bind to the hemoglobin in blood and not release. Since it doesn't release, fresh O2 (oxygen) cannot attach to the hemoglobin and the body (brain first) dies from oxygen starvation. When CO2 is produced through normal metabolism, it also attaches to the blood cells, but is released while traveling through the alveoli in the lungs, and fresh oxygen takes its place for the return trip to the body.
The catalytic converter on an auto mobile utilizes platinum as a catylist which causes any CO (carbon which is only partially oxydized) to finish burning (oxydizing) with the attachment of one more oxygen atom to the molecule. Tests in Los Angeles with super catylitic converters have shown that the exhaust coming out of the tailpipe actually had less CO than the air that was taken into the intake manifold. A catylitic converter leaves virtually no CO whatsoever in the exhaust. The gasses coming out of the exhaust manifold DO contain considerable CO, but it all finishes oxydation in the catylitic converter. One auto without the converter would possibly put out more CO than one generator (though auto engines are now engineered to squeeze out every calorie of energy possible through as complete oxydation as possible, while smaller IC engines like those on a generator are manufactured more with cost in mind). The catylitic coverters are so efficient, however, that one generator does indeed put out more CO (remember, we're talking CO, not CO2) than hundreds of cars. CO is poisionous to the human body. CO2 is not poisionous to the human body, but it is a greenhouse gas and affects climate change.
If catylitic converters were required on small IC engines, the amount of CO emitted in the exhaust would probably drop to less than 0.4% of what it currently is. The price of a catylitic converter is only 0.5% to 1% of the cost of a car, so that $200 price tag doesn't seem outrageous. But if you take a $400 generator and require a $200 catylitic converter to be attached, that's a 50% increase in price and consumers would be rather displeased, so it's a political trade off of where the most CO comes from, how much danger to public health there is, and how much resistance there is on the part of the public to measures that safeguard public health.
