Cleaner diesel fuel goes widely on sale in the US this week under new standards that could be a big boost for air quality and may encourage the use of more diesel-powered cars in the US market.
A rule introduced this year requiring a 97 percent reduction in the sulfur content of highway diesel fuel was phased in yesterday to an estimated 80 percent of the fuel sold in the US.
The next step comes in January when new diesel truck engines will be required to have special filters to curb emissions even further.
The overall result is "the single greatest achievement in clean fuel since lead was removed from gasoline more than 25 years ago," says US Environmental Protection Agency chief Stephen Johnson.
The agency estimates that by 2030, when most old engines will have been replaced, 20,000 premature deaths, tens of thousands of illnesses, and more than 7,000 hospital visits will be prevented every year.
Officials said cleaner diesel fuel will immediately cut soot emissions from any diesel vehicle by 10 percent.
But when combined with new engines hitting the road in January, it will enable emission reductions of up to 95 percent.
Environmental activists agreed that the new fuel would have a positive impact on air quality.
"We're shifting from incremental improvements in a still dirty engine to a very clean engine," said Richard Kassel of the Natural Resources Defense Council.
"Delivering low sulfur diesel fuel to the pump will pave the way for cleaner school buses and freight trucks that make the air safer to breathe," Environmental Defense senior attorney Vickie Patton said.
"We urge EPA to complete its important work securing cleaner diesel engines for America by lowering the harmful soot and smog from diesel locomotives and ships," she said.
In addition to the obvious benefit of reducing emissions from the 13 million heavy trucks using diesel fuel, some analysts say the new cleaner fuel could make it easier for automakers to introduce more passenger diesel cars that meet strict US emissions standards.
Only about 3.6 percent of new passenger vehicles registered in the US were powered by diesel, according to the Diesel Technology Forum, an industry group.
That is a sharp contrast to Europe, where about half the cars use diesel fuel.
But the US market is expected to rise, in part because of the better fuel economy from diesel.
"Diesel vehicles have always been 20 to 40 percent more energy efficient than comparable gasoline engines," said Allen Schaeffer, executive director of the Diesel Technology Forum, an industry group.
"With the switch to cleaner fuel, consumers will see more fuel-efficient diesel cars, pick-ups and SUVs [sport utility vehicles] on showroom floors in the years to come," he said.
Diesel vehicles are expected to make up 10 percent of the vehicles sold in the US by 2015 from the current rate of just 3.2 percent. That will help push the global market share of diesel vehicles to 26 percent from the current rate of 18 percent, consultancy JD Power forecast.