Image credit: USDOE , Emissions of Greenhouse Gases Emissions of Greenhouse Gases in the United States, 2008 (pdf file) Nitrous oxide, which has 298 times more climate forcing impact per unit weight than CO2, is an invisible gas emitted by the millions of tons from combustion

sources (see graphic). The internal combustion engine, as indicated in the figure, is the primary source of combustion-generated nitrous oxide (N2O). … Read the full story on TreeHugger

Here is the original post: 
"Laughing Gas" - No Laughing Matter For Vehicles