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Now, I thought about that, and the numbers seemed out of whack. I did a little mental arithmetic - at 25mpg, the car would be burning 1/25 = .04 gallon of gas per mile. If .04 gallon of gas contains almost a pound of carbon, then a full gallon would contain almost 25 pounds. But, even if gas were 100% carbon (and it's not - it has more elements in it), if a gallon weighs 25 pounds, then my 5 gallon gas can would weigh 125 pounds when full - and, I know it's not that heavy!

So, I sharpened my pencil, did the math more precisely, and sent the following message to the WSJ:

"The example refers to a car that gets 23.9 miles/gallon, which works out to .042 gallons per mile. So, if .042 gallons of gasoline produces .93 pounds of carbon, there would have to be 22.22 pounds of carbon in every gallon of gasoline (23.9 mi/gal X .93 #/mi = 22.22 #/gal). But a quick web search shows that a gallon of gasoline weights only 5.8 to 6.5 pounds. So, even if gasoline was 100% carbon, our hypothetical 23.9 MPG car could only emit .24 to .27 pounds of carbon per mile."

However, the reply that I got back from the WSJ made even less sense than their original quote:

"Below is the correction we ran on Nov. 17, 2007.

An automobile generates 0.93 pound of carbon dioxide per mile, according to the Environmental Protection Agency, so a car driven 93 miles generates 86.5 pounds of carbon dioxide, assuming the car gets a typical 23.9 miles per gallon. In Monday's Energy Journal Report, an article about how consumers can make an environmental difference incorrectly said such a car driven 93 miles generates about 100 pounds of carbon dioxide."

Am I crazy, or are the EPA and WSJ? I'm pretty sure that my math is sound, and that I am correct in assuming that mass is conserved in a simple chemical reaction like burning gasoline.

Mine isn't a political question - no, I don't like/respect the EPA any more than you do, and yes, the WSJ's editorial page can be pretty "out there". But, are my math and reasoning OK?