Using an instrument to measure fine particles -- those about 2 microns in size -- outside schools as buses dropped off students, the researcher found elevated levels from the exhaust. Fine particles are a concern because of the impact they can have on young lungs, said Randy Baker, chair of the Department of Respiratory Therapy at MCG and one of those conducting the research.
"The diesel fumes and particulates cannot only worsen asthma, it can actually lead to the development of asthma," he said. "So that's a problem."
They also found unexpected contributing problems at some schools, particularly when the grass was mowed during or just before the buses arrived, which really increased the particle count, said Kitty Hernlen, assistant professor in the MCG respiratory therapy program.
"We never really thought about when the grass is cut," she said. And that grass blast -- from dust, grass particles and grass pollen, presents an additional problem when combined with diesel fumes, Dr. Baker said.
"The diesel exhaust is kind of sticky, so actually grass pollens can stick to it," he said. "Those fine particles become sort of a perfect delivery vehicle as well."
School board member Jack Padgett, who also sits on the Richmond County Board of Health, said he planned to talk with maintenance about mowing at a different time.
"I really think we can clear a lot of that up," he said.
Richmond County has been using funds from the special purpose local option sales tax to update its fleet, adding 28 buses since 2006, said Director of Transportation Mike Shinn. It also got $154,000 from the Georgia Environmental Protection Division to retrofit 19 buses and is working to replace the oldest of its 220-bus fleet, Mr. Shinn said.
"We want to take advantage of all of these and make sure we're doing our part to clean up," he said. "We have done pretty well with the buses over the years."
Reach Tom Corwin at (706) 823-3213 or firstname.lastname@example.org.
Medical College of Georgia researchers are hoping to return to Richmond County schools next week to do follow-up testing of air quality outside schools. The MCG team also has an $8,000 grant from East Central Health District to do inside air quality testing, including inside school buses.