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Green Vehicle Guide

Greenhouse Gas Emissions from a Typical Passenger Vehicle

A typical passenger vehicle emits about 4.7 metric tons of carbon dioxide per year. This number can vary based on a vehicle’s fuel, fuel economy, and the number of miles driven per year. Click on the questions below to learn more about this estimate and see answers to common questions about greenhouse gas emissions from passenger vehicles.

  • Are there other sources of greenhouse gas (GHG) emissions from a vehicle?
    • In addition to carbon dioxide (CO2), automobiles produce methane, and nitrous oxide  from the tailpipe and hydrofluorocarbon emissions from leaking air conditioners. The emissions of these gases are small in comparison to CO2; however, the impact of these emissions can be important because they have a higher global warming potential (GWP) than CO2.
  • What are the tailpipe emissions from a plug-in hybrid electric vehicle (PHEV) or an electric vehicle (EV)? What about hydrogen fuel cell vehicles?
    • A vehicle that operates exclusively on electricity (an EV) will not emit any tailpipe emissions. A fuel cell vehicle operating on hydrogen will emit only water vapor.
    • Calculating tailpipe emissions for PHEVs is more complicated. PHEVs can operate on electricity only, gasoline only, or some combination of electricity and gasoline. A PHEV operating on electricity only (like an EV) does not generate any tailpipe emissions. When a PHEV is operating on gasoline only, it creates tailpipe emissions based on the PHEV’s gasoline fuel economy. Tailpipe emissions for a PHEV operating on both electricity and gasoline cannot be calculated without detailed information about how the PHEV operates. The overall tailpipe emissions for a PHEV can vary significantly based on the PHEV’s battery capacity, how it is driven, and how often it is charged. For more information, see the “My Plug-In Hybrid” calculator.
  • Are there any greenhouse gas emissions associated with the use of my vehicle other than what comes out of the tailpipe?
    • Driving most vehicles creates tailpipe greenhouse gas emissions. Producing and distributing the fuel used to power your vehicle also creates greenhouse gasses. Gasoline, for example, requires extracting oil from the ground, transporting it to a refinery, refining the oil into gasoline, and transporting the gasoline to service stations. Each of these steps can produce additional greenhouse gas emissions.
    • Electric vehicles (EVs) have no tailpipe emissions; however, emissions are created during both the production and distribution of the electricity used to fuel the vehicle. Visit the Beyond Tailpipe Emissions calculator to estimate GHG emissions for an EV in your region of the country.
  • I thought my gasoline was blended with ethanol. Does that change my tailpipe CO2 emissions?
    • Most of the gasoline sold in the U.S.is a mixture of gasoline and up to 10% ethanol (often referred to as E10). The exact formulation of the gasoline in your vehicle will vary depending on season, region in the U.S., and other factors. While your fuel economy when using an ethanol blend in your vehicle will be slightly lower than when using gasoline without ethanol, the COtailpipe emissions per mile will be similar. This is because ethanol has less carbon per gallon than gasoline.
  • How does EPA measure CO2 emissions from vehicles?
    • EPA and automobile manufacturers measure vehicle fuel economy and CO2 emissions using a set of standardized laboratory tests. These tests were designed by EPA to mimic typical driving patterns. EPA and the Department of Transportation use these values to ensure that manufacturers meet federal greenhouse gas and corporate average fuel economy (CAFE) standards.
    • For every new vehicle, the test results are used to determine real world fuel economy and CO2 emissions. These adjusted results are used on the Fuel Economy and Environment Labels and on Fueleconomy.gov.

Other useful sources include: