State OKs Limits on Emissions

State air quality officials Thursday approved stringent standards to cut sooty emissions from new big trucks and other diesel-powered vehicles by 90% by the end of the decade.

“Today’s action puts us solidly on the path to cleaning up diesel engines, something we have to do if we’re going to clean up the air in California,” said Michael Kenny, executive officer of the state Air Resources Board.

About 28% of the smog-forming nitrogen oxide emissions and 16% of the particle pollutants from vehicles come from big trucks and buses with heavy-duty diesel engines, according to the Air Resources Board.

“Diesel engines are the biggest source of motor vehicle-related [smog-forming] emissions,” said board Chairman Alan C. Lloyd.

The changes will be phased in beginning in 2007 and be completed by 2010. State air quality officials plan to press for more reductions from the thousands of heavy-duty diesel engines already in use. The officials say it will take perhaps 30 years until all diesel trucks and buses on the road are smokeless because the engines are long-lived and replaced slowly over time.

Acting in concert with the federal government, the decision by the board will for the first time require add-on devices on new big rigs, motor homes and school buses beginning in 2007. Once those changes are made, and heavy-duty diesels begin refueling with low-sulfur fuel at about the same time, it should usher in an era of virtually smokeless buses and trucks, officials say.

The new controls apply to California the same regulations that the U.S. Environmental Protection Agency approved during the Clinton administration and were upheld earlier this year by President Bush.

Stephanie Williams, vice president for regulatory affairs at the California Trucking Assn., said her organization broke ranks with national truck lobbies and supported the controls. She said the changes should boost fuel efficiency in big trucks by 25%, saving truck operators money on diesel fuel.

“We should be provided the cleanest possible technologies just like the motoring public has. It gets the regulators off our back when we are using the cleanest vehicles possible,” Williams said.

As the rest of the vehicle fleet has cleaned up, heavy-duty diesel trucks have not done as much to reduce sooty exhaust, which is increasingly linked to cancer, lung disease and poor visibility. Big trucks belching smoke plumes are a frequent source of complaints in the nation’s smoggiest state.

Under the rules the air board approved Thursday, emissions of nitrogen oxides and particulate matter must be reduced by 90% beyond stringent limits that have already been approved for new trucks commencing in 2004. The limits apply to big trucks, school buses, trash trucks, delivery vans and large motor homes. Strict limits for urban transit buses were approved last year.

Most of the reductions will come from the use of add-on devices, including soot traps and catalytic converters, which have been used since the mid-1970s on passenger cars.

Kenny said the next generation of controls will seek to retrofit those machines with controls similar to some being prescribed for new vehicles, although that action promises to be controversial.

In addition, Kenny said, cleaner standards will be needed for new off-road machines, ranging from diesel generators to farm and construction equipment. California will not be able to achieve health-based air standards unless deep cuts are made in the soot and smog-forming gases produced by diesel engines, he said.

“Diesel engines are a significant challenge for the future, and while we took a significant step in addressing that challenge, there is more to come,” Kenny said.