Despite this week's U.S. Supreme Court ruling, Southern California air pollution officials say they will still attempt to require most large-vehicle fleets to buy low-polluting trucks and cars -- a move that is certain to spark more court battles with industry groups.
On Wednesday, the high court invalidated rules that had allowed the South Coast Air Quality Management District to require private trash haulers, bus lines and other companies to buy low-pollution vehicles for their fleets.
But AQMD officials maintain the ruling does not bar them from imposing the same requirement on publicly owned fleets or on private firms that provide city services -- a contention hotly disputed by the engine manufacturers that prevailed in the lawsuit decided Wednesday.
The entire controversy boils down to a disagreement over diesel engines.
Manufacturers of diesel engines, along with an oil industry group, sued the AQMD because it had barred the owners of the private fleets from buying their products in the greater Los Angeles area, despite advances in clean diesel technology. The Supreme Court concluded Wednesday that the air district had overstepped its authority under the Clean Air Act.
Industry groups now say the decision should clear the way for street sweepers, bus lines and others bound by the rule to buy new diesel engines that emit far less pollution than older models.
"The Supreme Court decision is great for anyone who breathes, because it will allow some of the most promising technologies available to be used," said Anita Mangels, a spokeswoman for the Western States Petroleum Assn. "By insisting inappropriately on setting standards, South Coast was denying Southern Californians the ability to purchase one of the cleanest technologies."
But South Coast officials firmly maintain that the new diesel engines, although improved, are still far from clean compared with alternatives such as engines that burn natural gas.
"The fact is that diesel remains a much higher source of NOx emissions than natural gas, even with the new technology," said AQMD spokesman Sam Atwood, referring to nitrogen oxide gases, one of the main ingredients of smog. Atwood contends that the fleet rules allow companies to make a case for diesel trucks or any other technology if they can show it is as clean as natural gas.
Under the Supreme Court's ruling, key details of the decision are still to be worked out by a lower court in California.
