School buses' sooty exhausts highlighted

School buses' sooty exhausts highlighted
Environmentalists' studies emphasize diesel's role in dirty air
By STACY SHELTON
sshelton@ajc.com

DeKalb County's school bus manager is not surprised students riding diesel buses breathe in polluted air.

"We don't need a study to tell us that," said Dannie Reed, executive director of public transportation and planning for the DeKalb County school system.

But two environmental groups ran tests over three days last week at the DeKalb bus barn in Tucker to prove it — and to raise awareness that the federal government has promised to do something about diesel soot.

Preliminary findings from those tests, and ones conducted on Chicago school buses earlier this fall, show tailpipe emissions inevitably find their way inside buses. The lead scientist isn't ready to give specific numbers, although he will say the cleaner the exhaust, the cleaner the air children breathe while sitting on the bus. The exhaust also affects the air they breathe while waiting next to a bus that's idling.

Diesel engines, which power virtually all of metro Atlanta's 6,000 school buses, emit tiny fragments of carbon that public health officials believe is more harmful than pollution from gas-powered vehicles. The soot particles can lodge deep inside people's lungs and work their way into the blood stream. They can contribute to heart and lung diseases. In extreme cases, the particles can lead to death.

That worries Jonathan Grant, a DeKalb parent and member of the local school council whose children attend Evansdale Elementary School near Doraville.

"My daughter's on [safety] patrol. She breathes the exhaust

do something sooner rather than later."

Unfortunately, he said, cleaner buses probably will seem like a luxury during budget time.

The best diesel technology available is a particle-trapping filter attached to a bus fueled with low-sulfur diesel. Reed estimated retrofitting a bus with the device can cost between $2,500 and $7,000, depending on the size of the contract and the installer.

At a minimum, that would be a $2.5 million hit to the DeKalb school system. The low-sulfur diesel could add $90,000 to the $1.4 million the system already spends on fuel in a year, Reed said.

Despite the cost, he would like to see it happen. "I think it's the right thing to do," he said.

Preliminary results of the DeKalb bus tests conducted by the Clean Air Task Force and the Southern Alliance for Clean Energy indicate the soot-reducing technology works. Particles spewing from a standard school bus were, at times, more than 20 times greater than those coming from a bus with the clean fuel and filter, according to readings from researchers' hand-held measuring devices.

Senior scientist L. Bruce Hill of the Boston-based Clean Air Task wasn't ready to estimate how much of the pollution got into the school bus. But he knows some of it does — especially when carried in by a tailwind through an open window or door.

"Particles are basically eliminated by the technology," Hill said. "It's about 95 percent efficient."

But without low-sulfur diesel, the particle-trap technology is useless. And the special fuel isn't yet available in metro Atlanta. An interim but less effective technology is being used in Clayton County, which was awarded $75,000 by the state Environmental Protection Division to install oxidation catalysts on 60 buses. The catalysts improve engine performance, reducing the particles emitted by about 30 percent.

Next year, the U.S. Environmental Protection Agency will begin enforcing a standard for particle smog that metro Atlanta and many cities across the country are sure to fail. They're likely to be joined by Athens, Augusta, Columbus, Macon and Rome.

In addition, a federal rule will force fuel suppliers to provide low-sulfur, or clean-burning, diesel nationwide starting in 2006. And in 2007, new models of diesel-powered buses and trucks will have to meet super-low emission standards.

The tests on DeKalb school buses last week were largely designed to step up the pressure on EPA to make sure the Bush administration sticks to the deadlines. The environmental groups also want local governments, including school boards, to bridge the gap between now and 2007 by installing particle-trap technology on publicly owned diesel vehicles and by ordering low-sulfur diesel from suppliers.

"Let's go ahead and make this stuff happen. There's really no reason to wait," said Stephen Smith, executive director of the Knoxville-based Southern Alliance for Clean Energy.

Ron Methier, EPD air protection branch chief, said state and school officials have discussed the technology. But, he said, the costs involved make major changes unlikely before the federal mandates start.

"This will largely be a voluntary measure," Methier said. "School buses get a lot of people's attention because it's children who are transported in buses, standing at stops. They are exposed probably on a more regular basis than you or I just driving around breathing particulates."

DeKalb's Reed is hoping when the final test results come back in January he will be able to use them to attract grants from the feds and EPD to equip his 1,050-bus fleet with the particle-trapping technology.

"The school districts have got to be willing to pay a little bit more for this," Reed said. "Our mission statement says, 'We will provide safe, clean and dependable student transportation.'"