California issues draft diesel emissions plan

The California Air Resources Board (CARB), Sacramento, has released a draft risk-reduction plan outlining strategies to require particulate matter (PM) traps on all new and most existing diesel engines in California. The plan largely involves development of stricter emissions standards for diesel engines and vehicles but includes a reduction in allowable sulfur levels in California diesel in 2006 to the same standard the federal government plans to adopt in 2007, namely 15 ppm (wt).


The California Air Resources Board (CARB), Sacramento, has released a draft risk-reduction plan outlining strategies to reduce particulate matter (PM) emissions from diesel fuel consumed in the state.

The draft plan largely involves development of stricter emissions standards for diesel engines and vehicles but includes a reduction in allowable sulfur levels in California diesel in 2006 to the same standard the federal government plans to adopt in 2007, namely 15 ppm (wt) (OGJ Online, May 17, 2000). It also would require PM traps on all new and most existing diesel engines in California.

The draft plan can be viewed on CARB's website (http://www.arb.ca.gov/toxics/diesel/rrp.pdf). It is being made available for public comment.

CARB Executive Officer Michael P. Kenny said the organization's goal is to make new and existing diesel engines in the state up to 10 times cleaner than those currently in operation. Diesel engines affected by the proposal include heavy-duty trucks and buses, construction equipment, passenger vehicles, generators, and agricultural and marine engines.

CARB, a department of California's Environmental Protection Agency, estimates that about 27,000 tons/year of diesel PM is emitted into California's air. The proposal calls for CARB 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% from the 1.25 million diesel engines in the state.

The proposed plan calls for 12 control measures to be adopted in 1-5 years, with full implementation expected by 2010. Proposed strategies include the equipping all new diesel engines with PM traps, requiring low-sulfur diesel fuel, implementing in-use emission testing, mandating 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.

CARB estimates engine retrofit costs to range from $10 to $50/hp.

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