"I get a lot of fumes," she said, and she suffers from chronic bronchitis. "It seems to get worse in the fall and winter."
Medical College of Georgia researchers are trying to quantify just how much impact on air quality those buses are having at certain Richmond County schools.
Exhaust from school buses is the target of a national campaign to eliminate idling at schools while they wait to pick up students. The National Clean Diesel Campaign of the U.S. Environmental Protection Agency makes grants to districts to retrofit school buses with emission controls or to burn cleaner fuel.
There are roughly 390,000 diesel buses in use nationwide, and a third of them were built before 1990, Jim Blubaugh, the director of the clean diesel program, said. A 2007 survey found nearly 2,000 that were circa 1977 or older, he said.
"We've made great progress in getting a lot of those off the road," he said. "But it kind of just illustrates the extent of the age of this particular fleet and quite frankly the extent of the problem we're tackling."
The Georgia Environmental Protection Division also has made grants to 13 school districts, most in the metro Atlanta area or around Macon and Columbus, to clean up bus exhaust, said environmental compliance specialist Stacy Allman. All of those school districts were required to have no-idling policies, she said.
The division is working on a memorandum of understanding with Richmond County schools to provide $154,000 to retrofit 28 buses with emission controls so that they can meet current standards.
Richmond County drivers are already operating under a "no-idling directive" this year, and the Board of Education will consider making it a formal policy in the coming months, school spokesman Louis Svehla said.
Most school districts already have them, Mrs. Allman said.
The EPA's Clean School Bus USA, part of the Clean Diesel program, is working with 300 school districts to reduce or eliminate idling, Mr. Blumbaugh said. If all of those buses cut out 30 minutes of idling a day, he said, it would save $12 million a year in fuel costs.
Finding out what is coming out of those buses drew MCG Respiratory Therapy researchers Randy Baker and Kitty Hernlen to stand outside Spirit Creek Middle with a laser particle counter. It measures the amount of tiny particles in the air. Researchers had already made baseline readings during the summer and now late in the school day are awaiting the buses.
Dr. Baker, the chairman of the department, checks the display on the machine and it tells them it has counted 6,453 particles measuring 0.5 micron in the last minute.
It is these small fine particles that environmental officials worry about, said Alan Powell, an environmental engineer with the Environmental Protection Agency's Region 4 office in Atlanta.
"They're smaller, and they can get down into the lungs," he said.
Children's lungs are still developing, and they tend to breathe faster and are outside more, Mr. Blubaugh said.
The diesel filters can eliminate up to 90 percent of the emissions, said Rebecca Watts Hull, program manager with Mothers & Others clean air advocacy group. She held a particle counter in the exhaust stream of a bus in DeKalb County that had been retrofitted.
"The exhaust stream was actually cleaner than the ambient air," Ms. Watts Hull said. "I don't know if that is saying something really scary about Tucker, Ga.'s, ambient air quality or what the filter is doing but it is remarkable the difference that those filters make."
So far at Spirit Creek, with no buses in sight yet, the readings are good.
"It's much lower now than it has been on other days that we've been here," Dr. Baker said. Then a bus rolls past and sits idling several feet away.
"I can smell that right there, those diesel fumes, just from that turn-around," he said.
The count jumps from mid-6,000 to 10,500.
A minute later, kids file out the door into lines and begin boarding buses. After 12 buses have come and gone, most sitting no more than a couple of minutes with the engines running, the count is up to nearly 12,000. By his count, Dr. Baker said, only four idled.
"It really wasn't bad at all," he said.
At 4:30 p.m., just before the last bus leaves, the count is up to over 21,000. Other days at other schools, it has topped 30,000, Dr. Baker said. Researchers hope to take readings inside the buses in the future, he said.
"Oftentimes these buses, especially when the windows are closed, are like little environmental exposure chambers," he said. "And the particles and the volatile compounds really pick up as the kids are in the bus."
The real target of the research, however, is the parents sitting in their idling cars at the front of the school.
"I think the ultimate goal is (to) raise awareness and show some facts to the families and get the families and schools involved," Dr. Baker said. "I think the board of education has been very supportive of this so far."
Reach Tom Corwin at (706) 823-3213 or firstname.lastname@example.org.