17. An automobile engine produces 20 pounds of carbon dioxide for every gallon of gas it burns, or about 1 pound per mile.

I don't dispute this, but am curious to know how it happens. A gallon of gasoline weighs a bit over six pounds. It seems like a stretch to generate 20 pounds of CO2 (along with all the nitrogen oxide, all the hydrogen compounds, and the considerable weight of water) from that six pounds of gasoline.

18. A hybrid car produces less than one half pound of CO2 per mile.

Here's proof that statistics don't lie, but people lie with statistics. Notice the careful juxtaposition of the two statements: "An automobile engine produces 20 pounds of carbon dioxide for every gallon of gas...", and "A hybrid car produces less than one half pound of CO2 per mile." Wow! The hybrid car only produces one-fortieth the amount of pollution!

Wait a minute -- the first statement is pollution per gallon, the second statement is pollution per mile. Take a car getting 30 MPG, and it is producing 2/3 pound of CO2 per mile -- not that different from the hybrid. Keep in mind that even a hybrid car uses "...an automobile engine [that] produces 20 pounds of carbon dioxide for every gallon of gas...". It just gets more miles per gallon.

Another factor to consider in all of this... the EPA does not rate vehicular pollution on the basis of amount of pollution per gallon of fuel burned, but instead on amount of pollution generated per mile traveled, regardless of amount of fuel consumed. This applies to automobiles, trucks may be different.

tanstaafl.