SACRAMENTO –  California today announced new, tougher exhaust standards for the diesel engines that power big-rig trucks, trash trucks, delivery vans and other large vehicles.  The new standards take effect starting with the 2007 model year.

    "These new regulations will reduce diesel soot and smog-forming emissions from new, large diesel engines by another 90 percent," said Dr. Alan Lloyd, Chairman of the California Environmental Protection Agency's Air Resources Board (ARB).  These emission reductions will be achieved by equipping new diesel engines with exhaust aftertreatment devices.

    By 2010, ARB staff calculates, the 2007 standards will reduce 50 tons-per-day (TPD) in smog-forming emissions and 3 TPD of cancer-causing particulate matter (PM) statewide.  ARB's new standards mirror U.S. Environmental Protection Agency diesel engine standards, also scheduled to go into effect in 2007.

    Compared to standards already set for 2004, the standards adopted today will bring a 90 percent reduction in smog-forming nitrogen oxide (NOx) emissions and a 90 percent reduction in PM emissions.

    Aftertreatment devices to reduce harmful air emissions in exhaust first appeared on gasoline-powered cars and light truck engines since the mid-1970s.  However, as stringent regulations cut harmful air emissions from gasoline engines by more than 95 percent, emissions from new large diesel engines came under increasing scrutiny because they lack aftertreatment devices.

    "Reducing the health-damaging emissions from diesel engines is one of the ARB's top priorities.  Diesel engines are the biggest source of motor vehicle-related NOx emissions," Lloyd added.