SACRAMENTO – The California Air Resources Board (ARB) today released its draft risk reduction plan (https://ww3.arb.ca.gov/diesel/dieselrrp.htm)that outlines strategies to require particulate matter (PM) traps on all new and most existing diesel engines in California.

        ARB Executive Officer Michael P. Kenny said, "Our goal, over the next 10 years, is to make new and existing diesel engines in California up to ten times cleaner than those in operation today"

       "Diesel is the lifeblood of California commerce, but its associated emissions are causing serious health problems.  This plan will help protect the health of our citizens while maintaining California's vibrant economy," he added.

        Diesel engines that are affected by the proposal include heavy-duty trucks and buses, construction equipment, passenger vehicles and trash haulers, generators, agricultural and marine engines.

        The ARB estimates that about 27,000 tons of diesel PM are emitted each year into California's air.  The staff proposal calls for ARB to work with local and federal agencies, engine manufacturers, fuel providers and the public to develop additional emission standards to reduce diesel emissions by up to 90 percent from the 1.25 million diesel engines in the state.

       The proposed plan calls for 12 control measures to be adopted within one to five years, with full implementation by 2010.  Some of the strategies proposed in the plan consist of equipping all new diesel engines with PM traps, requiring low-sulfur diesel fuel, in-use emission testing, broader use of alternative fuels and providing funding to offset the cost of upgrading to cleaner alternative fuel engines.  The plan also recommends retrofitting existing diesel engines with PM traps.

       The ARB estimates the cost to range from $10 to $50 per horsepower for the retrofit.  In addition, ARB will ensure that the clean diesel fuel needed to enable advanced emission control technology will be available.

       In 1998 the ARB identified diesel particulate matter as a Toxic Air Contaminant, which lists the compound as a known human carcinogen.  As part of the identification process, Cal/EPA's Office of Environmental Health Hazard Assessment, the state's toxicology agency, completed a health risk assessment which evaluated the potential of diesel PM to affect human health.  The findings revealed that diesel PM can cause health problems ranging from respiratory illness, heart problems, asthma and cancer.