Easy rider, easy polluter.

A Swiss study published in the 1 January 2006 issue of Environmental Science & Technology shows that motorcycles collectively emit 16 times more hydrocarbons, 3 times more carbon monoxide, and "disproportionately high" levels of other air pollutants, compared with passenger cars. Two- and three-wheeled vehicles are widely used in Asia. Because they are not a primary means of transportation in developed countries, however, not a great deal of attention has been paid to emissions from these vehicles. But a U.S. EPA rule that took effect in January 2006 requires manufacturers to reduce emissions of hydrocarbons and nitrogen oxides by 60%. By 2010 the EPA estimates the rule will save about 54,000 tons of emissions and 12 million gallons of fuel per year.