Cobb County experiments with buses running on diesel-vegetable oil mix

MARIETTA - Cobb County is experimenting with buses that run on a cleaner-burning, diesel-vegetable oil fuel mix to reduce pollution. <br> <br> But if the tightly budgeted district can&#39;t get a grant to fill the tanks of more buses with the alternative fuel called biodiesel, the experiment will be limited to the three already using it. Cobb has a fleet of more than 900 school buses. <br> <br> The fuel is a mix of 20 percent vegetable oil, usually soybean, and 80 percent diesel. According to the U.S. Environmental Protection Agency, biodiesel releases less carbon monoxide and fewer hydrocarbons and particles than petroleum-based diesel. It works with most diesel engines. <br> <br> But the EPA has found biodiesel can increase nitrogen oxide emissions, a key ingredient of smog. <br> <br> The state has not encouraged school systems to switch, said Marlin Gottschalk, senior policy adviser for the Georgia Department of Natural Resources. <br> <br> Biodiesel also is more expensive than regular diesel fuel - about 37 cents more per gallon. <br> <br> In metro Atlanta, 13 counties violating the Clean Air Act risk losing federal highway dollars. <br> <br> The Cobb district began using biodiesel last year, anticipating tougher requirements for federal clean air standards, said Roger Kubler, assistant superintendent for business services.