SF breathes easier
The city of San Francisco’s entire fleet of diesel vehicles—all 1,500 of them—are now running on biodiesel. The conversion project had been underway for a year and is intended to reduce diesel exhaust linked to higher rates of asthma and premature death, reports the New York Times. The vehicles run on B20 fuel, a mix of 20 percent soy-based biofuel and 80 percent petroleum diesel fuel. The conversion is part of the city’s plans to cut greenhouse gas emissions to 20 percent below 1990 levels by 2012.