Scientists led by a team at Caltech have developed a new method for potentially removing nearly all sulfur compounds from gas and diesel fuel.Sulfur compounds in fuels such as gasoline and diesel create air pollution when the fuel is burned. To address that challenge, large-scale oil refinery processes remove the majority of sulfur from fuel down to a government-mandated level. The new technique, however, has the potential to reduce sulfur down to a fraction of that amount, which would further reduce air pollution and extend the lifetime of vehicles' catalytic converters, which control tailpipe emissions.