Clean diesel vehicles run cleaner than diesel engines from the past because of the adoption of ultra-low sulfur diesel (ULSD) fuel as the diesel fuel standard in the United States as well as advances in diesel engine technologies that trap or clean diesel exhaust prior to emitting into the atmosphere.

THE FUEL: ULTRA LOW SULFUR DIESEL (ULSD)
The US EPA began phasing out low sulfur diesel in 2006 by requiring refiners and importers to import and produce at least 80% ULSD. By December 2010, all highway diesel in the United States must be ULSD. ULSD has been the standard in California since September 2006. ULSD has 97% less sulfur content than its predecessor low sulfur diesel and is fully compatible with any diesel engine. Diesel engines manufactured after 2006 run solely on ULSD.

ENGINE TECHNOLOGY
There are two primary technologies used in clean diesel engines: particulate traps and catalytic converters or a combination of both.
Diesel particulate filters or traps are ceramic devices that collects diesel exhaust • particulate matter, breaking it down into less harmful emissions. When the filter is full it regenerates.
Catalytic converters transform toxic emissions to non-toxic gases by mixing exhaust with an additive. Most commonly found on newly manufactured clean diesel vehicles.

ENVIRONMENTAL IMPACT
ULSD reduces 2.6 million tons of smog-causing nitrogen oxide emissions and soot or particulate matter by 110,000 tons a year. Particulate filters reduce particulate matter associated with asthma and air pollution by 60-90% and significantly reduces greenhouse gas emissions.

BENEFITS
Diesel emissions have historically been linked to negative air and human health impacts. With the adoption of ULSD, filter retrofitting regulations and new clean diesel vehicles, an estimated 8,300 premature deaths, 5,500 cases of chronic bronchitis and 17,600 cases of acute bronchitis in children will be prevented annually as well as an estimated avoided 360,000 asthma attacks and 386,000 cases of respiratory symptoms in asthmatic children every year. Totaling a prevented 1.5 million lost work days, 7,100 hospital visits and 2,400 emergency room visits for asthma will be prevented. ULSD accounts for 70% of all US fuel production.1 Diesel engines also experience higher performance and lifetime than traditional gasoline powered vehicles.

DISADVANTAGES
Retrofitting diesel vehicles with particulate traps can be extremely expensive. However, there are many credit and incentive programs available from the state.2

VALLEY ACCESS POTENTIAL
Clean diesel vehicles are on the market and available at Valley dealerships. Particulate filters are available from a number of manufacturers and can be retrofitted by diesel service technicians and mechanics. ULSD has been the standard in California since 2006 and is available at retailers around the Valley.

For more information on clean diesel visit the U.S. EPA at www.epa.gov/diesel/

1 Energy Tomorrow http://www.energytomorrow.org/Diesel_Prices.aspx (last accessed April 23, 2009)
2 CARB http://www.arb.ca.gov/diesel/rppot.htm (last accessed April 23, 2009)