Environmentalists and regulators said not enough is being done to cut pollution from the more than 5 million tractor-trailers, dump trucks and other heavy vehicles, while at the same time the government is pushing for cleaner-running cars and sport utility vehicles.
"There's probably no more offensive air pollution than the thick, noxious pollution from big trucks," said Bill Becker of the Assn. of Local Air Pollution Control Officials.
The Environmental Protection Agency is looking at requiring low-sulfur diesel fuel; EPA is already proposing cutting sulfur content in gasoline by 90%. Diesel fuel currently contains almost twice as much sulfur as gasoline.
Rick Kassel of the Natural Resources Defense Council complained that trucks are not required to have pollution-controlling catalytic converters. But Becker noted that they aren't going to be seen on heavy trucks until the sulfur in diesel fuel is dramatically reduced. Sulfur interferes with pollution control equipment.
Don DeFosset, head of the truck group at Navistar International, says he's glad to see the government looking at low-sulfur diesel. "We believe the diesel engine is the only way for a truly clean engine," he says, "once we get the sulfur out."
At a meeting of The Maintenance Council earlier this year, engine manufacturers said that for the next big emissions cut in 2002, they are looking at new technologies for truck engines, such as exhaust gas recirculation. Another thing they're studying is exhaust aftertreatment - similar to the catalytic converters found on cars and light trucks. One way to do this on heavy trucks is to use a chemical, actually a fertilizer, called urea. When injected into the exhaust, it turns to ammonia and burns off NOx. However, this would mean adding another small tank on the truck - and there aren't exactly an abundance of urea pumps at your favorite truckstop.