The Emissions Calculations are based on:

• Fuel consumption of the corporate fleet customers and related data provided by Hertz to Terrapass, and is collected by Hertz at the time of vehicle return.
• Emission factors used by Terrapass are provided by the U.S. Environmental Protection Agency (USEPA) and U.S. Department of Energy (DOE).
• Calculations are expressed in metric tons (mT, one metric ton is the equivalent of 2,205 lbs.)

“Carbon dioxide equivalent” of “CO2e” is a term for describing different greenhouse gases in a common unit. For any quantity and type of greenhouse gas, CO2e signifies the amount of CO2 which would have the equivalent global warming impact according to published scientific standards, updated periodically. A quantity of GHG can be expressed as CO2e by multiplying the amount of the GHG by its GWP. E.g. if 1kg of methane is emitted, this can be expressed as 25kg of CO2e (1kg CH4 * 25 = 25kg CO2e). “CO2e” is a very useful term for a number of reasons: it allows “bundles” of greenhouse gases to be expressed as a single number; and it allows different bundles of GHGs to be easily compared in terms of their global warming impact.
The three main greenhouse gases (along with water vapor) and their 100-year global warming potential (GWP) compared to carbon dioxide are: (1)

• 1 x – carbon dioxide (CO2)
• 25 x – methane (CH4) – I.e. Releasing 1 kg of CH4 into the atmosphere is about equivalent to releasing 25 kg of CO2
• 298 x – nitrous oxide (N2O) – Ii.e. Releasing 1 kg of N2O into the atmosphere is about equivalent to releasing 298 kg of CO2