California Air Resources Board

SACRAMENTO – California's 1.2 million diesel engines will all emit less pollution when the state completes its turnover to the nation's cleanest diesel fuel on September 1, 2006. The switch to new Ultra Low Sulfur Diesel (ULSD) fuel is in preparation for new, cleaner-operating heavy-duty trucks equipped with advanced emission control systems that debut next January.

ARB Chairman, Dr. Robert Sawyer said, "September 1 is an important date for California because we now have the nation's cleanest diesel fuel. This new diesel fuel allows us to proceed with our plans to cut diesel emissions by 85 percent in 2020 and to meet Governor Schwarzenegger's goal of cutting air pollution by one-half."

The switch to Ultra Low Sulfur Diesel has been planned for the past year as federal and state governments, refiners, environmentalists and businesses prepare for the introduction of clean-burning diesel big rigs on January 1, 2007. Those new vehicles will meet the tightest emission standards ever set for heavy-duty trucks and buses and require very low sulfur fuel to operate properly. Without clean fuel those engines cannot use new emission control equipment such as particulate traps to control toxic particulate soot and catalysts that limit ozone-forming nitrogen oxide emissions, the most common pollutants emitted by diesels.

The new fuel also will allow the ARB to continue its diesel risk reduction plan (RRP), a set of regulations designed to cut the public health risks of diesel particulate by 85 percent in 2020. The risk reduction plan calls for slashes in diesel particulate from a number of pollution sources such as trucks and buses, farm and construction equipment as well as pumps and boilers. Locomotives and harborcraft such as tugs must begin using ULSD by January 1, 2007.

The diesel RRP is closely tied to the recently released ARB Emission Reduction Plan for Ports and Goods Movement that seeks to cut deaths in California associated with efforts to transport goods in and out of the state by truck, train or ship. ARB scientists estimate that currently up to 2500 Californians die prematurely each year from exposure to diesel exhaust caused by goods movement. The emission reduction plan will cut the number of premature deaths to 800 despite a three-fold rise in goods movement activity by 2020.

Some California refiners have been producing some ULSD for several years. That limited amount of ULSD allowed the ARB to develop rules requiring school and transit buses, as well as garbage trucks, to use ULSD to better protect the health of children and Californians in urban areas, where these vehicles generally operate.