Beyond CO2

We are addressing other greenhouse gases like hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), nitrous oxide (N2O) and sulfur hexafluoride (SF6). We have prohibited SF6 in tires and PFCs in open systems since 1999. We are minimizing the use of HFCs in vehicle air conditioning and prohibit the use of HFCs in other on-board vehicle applications (e.g., as used in some spare tire kits). We are working with our suppliers to optimize air conditioning efficiency, reduce coolant leakage rates and investigate alternatives. We are also actively conducting research to evaluate the environmental fates of potential alternative air conditioning coolants to replace HFC R-134a. We prohibited the use of SF6 in magnesium casting as of January 2004 through our Restricted Substance Management Standard.

Although the vast majority of greenhouse gases from motor vehicle tailpipe emissions are in the form of CO2, relatively small amounts of other greenhouse gases are emitted. Methane (CH4) is a volatile organic compound responsible for only about 0.3 to 0.4 percent of the warming potential attributable to CO2 emissions from vehicles. CH4 emissions will continue to be reduced as a result of efforts to reduce hydrocarbon emissions and improve fuel economy. We also try to minimize N2O tailpipe emissions (which contribute about 1 to 3 percent of the warming potential attributable to vehicle CO2 emissions), even though N2O is not among the criteria pollutants.