State Mandates ‘Smoke-Free’ Diesels by ’94

Times Staff Writer

Heavy diesel trucks and buses should run “virtually smoke free” by the early 1990s as a result of stringent particulate emission standards set Friday by the California Air Resources Board, the first such controls ever.

These standards, made possible by the development of a cigarette filter-like soot trap, will begin to take effect in 1988. By 1994, diesel trucks and buses will not be allowed to emit more than 0.1 gram per mile. That would cut soot emissions by 62 tons daily, a 50% reduction in particulate pollution statewide.

Friday’s 8-0 vote on soot emissions capped a new, three-pronged attack against air pollution designed also to convince the U.S. Environmental Protection Agency that California is making a good-faith effort to meet federal Clean Air Act standards, even though compliance is not expected until long after the 1987 deadline.

Compliance by 2000


By even the most optimistic projections, California will not meet those standards until the year 2000.

States that do not meet the federal clean air standards by 1987 could lose federal highway funding or have other “sanctions” levied against them, ARB Chairwoman Jananne Sharpless said. But she added that she hopes the board’s “vigorous regulatory program” will persuade federal regulators to grant the state more time to achieve the mandatory air quality standards, set by Congress in 1970.

Meeting in Los Angeles, the board on Thursday also greatly tightened controls over auto emissions for nitrogen oxide and, in a third vote Friday, brought California’s emission controls for gasoline-powered trucks in line with federal standards.

The combined actions will reduce the amount of nitrogen oxide being released into the air by 190 tons a day, a 15% reduction statewide.


Adoption of these new regulations constitutes “the most significant regulatory actions the board has taken in the past five years,” Sharpless said. “This shows that we are committed to a vigorous regulatory program.”

The ARB’s actions follow its recent “pledge” to federal regulators to further combat air pollution by reducing hydrocarbon pollutants by 25% by the year 2000, and by identifying other toxic emissions from autos, like benzene, and then setting standards to control them, ARB spokesman William Sessa said.

“We are trying to convince the federal regulators that they should distinguish between states that are really trying and those that don’t, when it comes to sanctions,” he said.

While the tightening of nitrogen oxide standards was strongly opposed by auto makers, who said they cannot meet such stringent standards, the board’s action Friday to attack the problem of black, sooty smoke belching from mass transit buses and long-haul trucks glided through the hearing virtually without opposition.


The new soot restrictions apply only to new vehicles. Beginning in 1988, emissions can be no more than 0.6 gram per mile and and by 1994 must be down to 0.1 gram, a virtually smokeless level.

The addition of the soot traps will increase vehicle costs by about $736, but the ARB staff contends the cost will be partly offset by increased fuel efficiency.

Because urban mass transit vehicles contribute so significantly to the soot problems, the ARB accelerated the compliance timetable for these vehicles, ordering that urban buses emit no more than 0.1 gram by 1991, three years earlier than trucks and buses.

The new diesel emission standards are a first step toward reducing particulates in the air, a high priority in Southern California because, while nitrogen oxide levels have dropped markedly in recent years, the amounts of particulates are rising. Diesel trucks and buses contribute significantly to this problem.