I found this very interesting to find out, how to quantify potential loss, societal cost due to gas emission from our transportation. Let’s do the math now!

First thing we need to know is how much carbon dioxide (CO2) will be produced for each gallon gasoline burned. When gasoline burns, carbon and hydrogen separate. The hydrogen combines with oxygen to form water (H2O), and carbon combines with oxygen to form carbon dioxide (CO2). A carbon atom has a weight of 12, and each oxygen atom has a weight of 16, so a single molecule CO2 will have weight of 44 (12 from carbon and 32 from two oxygen molecules).

Therefore, to calculate the amount of CO2 produced from a gallon of gasoline, the weight of the carbon in the gasoline is multiplied by 44/12 or 3.7.

Gasoline has a weight of 6.3 lbs. Since gasoline is about 87% carbon and 13% hydrogen by weight, the carbon in a gallon of gasoline weighs 5.5 pounds (6.3 lbs. x .87). We can then multiply the weight of the carbon (5.5 pounds) by 3.7, which equals 20 pounds of CO2!

Now, how can we get the dollar sign? Well, Bion Howard wrote a paper a few years back entitled “Simplified Pollution Avoidance Calculation for Builders”. An article was published in the Northeast Sun (publication of the Northeast Sustainable Energy Association) in the spring of 1993. He placed the dollar value of the societial costs at 4.8 cents per pound ($96/ton).

Now, you catch the idea, if the societal cost is 4.8 cents per pound of CO2, that would mean, for each gallon our vehicle consumes, basically we burden our environment 4.8 cents/pound x 20 pounds, equal to $0.96/gallon. And that is very expensive.

In case you are little bit confuse with the unit metric, I will use another unit conversion which is International Unit. All you need to do is knowing your gasoline density. Using unit conversion here, I take example of gasoline that has 0.737 kg/L. If I buy 1 litre of gasoline, the weight of it would be 0.737 kg. Now, assume carbon content of your gasoline is 80%, that would make carbon weight for 1 litre gasoline is 0.59 kg. We multiply this by 3.7 (read above again if you do not know where this comes from), equals to 2.18 kg of CO2.

Based on societal value for each pound CO2 produced, we now can calculate societal and environment cost due to our vehicle emission. We have 2.18 kg of CO2/litre of gasoline times 9.6 cents/kg, that would produce 20.93 cents = $0.21/litre gasoline. That’s it, hope you get the point.

**Reference(s):**

http://www.epa.gov/otaq/climate/420f05004.htm

http://www.ibiblio.org/london/renewable-energy/mailarchives/greenbuilding2/msg01253.html