Fleet Emissions and the Effects on the Environment

Mar 01, 2013

Here’s a fact: excessive amounts of carbon dioxide (CO2) in the earth’s atmosphere contributes to global warming.   Day after day highway vehicles burn fuel that leads to the creation of carbon dioxide.   Why should you as a fleet manager care about how much CO2 your fleet emits?  Because you can not only use this information to determine how much your fleet impacts the environment, but you can make better, well informed decisions about vehicle maintenance and vehicle purchases.

How 6 Pounds of Gasoline Creates 20 Pounds of Carbon Dioxide

So just how much CO2 are we talking about?

A gallon of gasoline weighs roughly 6.3 pounds. It seems unlikely that a gallon of gas could create 20 pounds of carbon dioxide when burned. Interestingly enough, the weight of the carbon dioxide doesn’t come from the gasoline itself but from the oxygen in the air.

When gas burns, carbon and hydrogen separate. The hydrogen combines with oxygen to form water (H2O) and carbon combines with oxygen to form carbon dioxide.

A carbon atom weighs 12 amu (atomic mass units), and each oxygen atom weighs 16 amu, which means each single molecule of CO2 weighs 44 amu (12 from carbon and 32 from oxygen).

Therefore, to calculate the amount of CO2 produced from a single gallon of gasoline, multiply the weight of the carbon in the gasoline by 3.7 (44 ÷ 12).

Since gasoline is about 87% carbon and 13% hydrogen by weight, the carbon in a gallon of gasoline weighs 5.5 pounds (6.3 pounds x 0.87).

When we multiply the weight of the carbon (5.5 pounds) by 3.7, our total is 20 pounds of CO2!

Bottom line—fuel-efficient vehicles not only save your business money but they help protect the environment from harmful CO2.

Sources: Physical and chemical properties of gasoline: Department of Energy (DOE), Alternative Fuels Data Center (AFDC), http://www.afdc.energy.gov/pdfs/afv_info.pdf.