Dirty truck emissions verified HD: Many diesel rigs fail initial tests

July 30, 1993|By Douglas Birch | Douglas Birch,Staff Writer

Forty percent of the heavy diesel trucks tested so far in Maryland's new voluntary emissions-control program flunked, spewing smoke dirtier than an industry-recommended standard.

But state Department of the Environment officials greeted the news cheerfully yesterday.

That failure rate is very close to what they expected when the program for heavy-duty rigs began seven weeks ago, officials said at a press conference in West Friendship, held at a truck weigh station on Interstate 70.

The 18-month, penalty-free "pilot program," they said, is supposed to encourage the owners of soot-belching vehicles to tune up their engines and clean up the air. The $160,000 effort is also intended to help the state decide in 1995 whether a mandatory testing program for heavy-duty trucks, defined as those weighing more than 8,500 pounds, is needed.

"We'll have some hard data to take to the General Assembly and the trucking industry," said Robert Perciasepe, Maryland's secretary of the environment.

Gasoline-powered cars and light trucks must be tested once every two years, to ensure that their exhaust is no dirtier than state standards. But Maryland does not require the testing of diesel vehicles and sets no exhaust standards for them -- due in part to the opposition of the trucking industry and concerns about the cost of a diesel testing program.

Del. Jennie Forehand, a Montgomery County Democrat who has long fought for diesel truck- and bus-emissions testing, praised the pilot program, saying she sees it leading to mandatory testing.

"We can no longer apply these preventive measures to automobiles while exempting large diesel trucks and buses," she said.

A state environmental official said California and Colorado have mandatory truck-emissions tests.

Allen R. Schaeffer, a spokesman for the American Trucking Associations of Alexandria, Va., said Maryland's pilot program will not only help clean up the air but will encourage truckers to save diesel fuel and money.

"Black emissions coming out of the exhaust pipe really means unburned fuel," he said.

Under the federal Clean Air Act, Maryland must reduce ozone-forming emissions in the Baltimore area by 2005 or lose tens of millions of dollars in federal highway money. But even clean-air advocates concede that diesel rigs aren't the major problem.

Car is chief polluter

"The personal car is the biggest source of air pollution," said Glen Besa, a spokesman for the American Lung Association of Maryland.

Big diesel trucks account for just 4.4 million of the 113 million miles driven in Maryland daily, and generate only 2 percent of the volatile organic compounds and 8 percent of the nitrogen oxides spewed into the air. These two invisible tailpipe gases react with sunlight to create ozone, the major ingredient in smog.

But diesel smoke by itself is a recognized carcinogen, clean-air advocates point out. And diesel trucks are a significant source of another form of health-threatening pollution: tiny particles of soot.

Recent studies suggest that fine airborne soot particles, which are drawn deeply into the lungs, may cause tens of thousands of deaths across the nation each year -- even though soot levels in Maryland and elsewhere generally fall within legal limits.

"Scientific evidence has shown us that particles are even more important than we thought they were in the past," Mr. Perciasepe said.

Adrian Wentzel, 49, of Middletown, a trucker hauling a load of fuel oil from Baltimore to Hagerstown before noon yesterday, pulled up to the truck scales and agreed to have his rig tested. He was greeted by a small mob of reporters.

James D. "J. D." Watkins, one of two truck exhaust testers, held a headphone-shaped "smoke-meter" on a pole up to one of the twin pipes on Mr. Wentzel's gleaming red-and-white tractor, which he drives for a New Market trucking company.

Rig passes easily

L The rig passed easily -- with a high score of 31 out of 100.

Smoke thickness is measured on the basis of opacity, with 0 percent absolutely clear and 100 percent totally black. Maryland does not enforce any diesel smoke standard. But the diesel Engine Manufacturers Association recommends, for efficiency's sake, that opacity not exceed 55 percent. Sixty percent of the trucks tested so far have met that standard.

"It's a good idea," Mr. Wentzel said. "It shows that your truck is performing right. You're going to get your best fuel mileage."

Mr. Schaeffer of the American Trucking Associations said it was an open question whether Maryland's pilot program would show that there is a need for mandatory testing for heavy-duty trucks.

'Pretty darn clean'

"I just have to see," he said. "I think the experience in other states suggests there are some bad actors out there. But, overall, our trucks are pretty darn clean."

Beginning Oct. 1, he said, the Clean Air Act requires that diesel fuel contain 80 percent less soot-causing sulfur. On the same day, manufacturers are required to begin building cleaner-burning diesel engines.

As these new trucks replace older models, he said, overall soot particle emissions from big trucks should decline. "In two years there may not be a need for a [mandatory] program," he said.

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