GREENVILLE, N.C. -
They carry your most precious cargo, sometimes for hours a day; but school buses have a hidden danger that's threatening your child's health.
"I think everybody needs to be worried," says James Kenny, MD, a retired pulmonologist who's studied air pollution extensively.
The source: dangerous diesel fuel exhaust.
Dr. Kenny says diesel exhaust is made up of two main parts: gases and soot. Those contain dangerous levels of carbon monoxide, sulfur oxides and nitric oxides, to name a few.
Many federal agencies classify it as a probable human carcinogen.
"The health risks with diesel exhausts are mainly asthma, evolving into chronic obstructive pulmonary disease, and early disability and then possible cancers," Dr. Kenny says.
He says pollution can get trapped inside the bus where tiny particle levels can be 5-10 times higher than outside.
Even scarier is that your child's symptoms can be difficult to detect. Dr. Kenny says wheezing is the only obvious side effect. That could eventually develop into asthma, which he says is the top reason why students miss school.
"Statewide, 30 percent in the 6th grade have asthma," he says of a UNC-Chapel Hill study. "That's a significant amount and you can't educate an empty desk."
So how does your child's school bus measure up? It's tough to tell.
North Carolina does not require emissions tests for school buses or for any other diesel-powered car. That's because the Environmental Protection Agency has not yet developed a reliable test for diesel engines.
There's also no state law that regulates air quality within the buses, so it's up to the North Carolina Division of Air Quality and the Department of Public Instruction (DPI) to reduce emissions.
"I think we all know that our most valuable commodity is the children," says Brock Letchworth of Pitt County Schools. "That's what we're always trying to protect and that is inside the classrooms, that's outside the classrooms on buses as well."
DPI requires school systems statewide to adopt a reduced idling policy to be eligible for any state transportation funds linked to increasing fuel prices.
Letchworth says buses in his district are not allowed to idle longer than five minutes at a time. Buses must park diagonally, rather than single file, and take shorter routes with fewer stops.
They're strategies Letchworth says also save thousands of dollars a year in fuel costs.
"While we're protecting the children, we're also protecting the bottom line," he says.
Newer buses made after 2007 are much cleaner than older ones, thanks to stricter new EPA standards. But with budget cuts, not many school systems can afford them.
Instead, many schools are investing in cheaper pollution-cutting filters for older buses that can reduce emissions by up to 90 percent.
Experts say the best option for long-term solutions would be to start using an alternative fuel source like biodiesel. It's a cleaner-burning version of diesel made from natural, renewable sources such as vegetable oils instead of petroleum.
Green Circle North Carolina is leading the efforts here in the East. Co-owner Dean Price says local farmers make vegetable oil and sell it to local restaurants. The restaurant owners then turn around and sell or donate it back to his company.
Green Circle NC then turns it into biodiesel. Price says when you use it in school buses it improves the air quality by 80 percent compared to fossil fuels.
But beyond the health benefits, he says it could also provide an economic boost.
"Five years ago, the restaurant owners were having to pay to get rid of this substance," Price says of used vegetable oil. "It's what I call the perfect Cinderella story. This trash has now turned into treasure where the restaurant owners are now getting paid for their waste product. This will have ripple effects through the entire economy of enc for decades to come."
Pitt County Schools participates in price's Biodiesel for Schools program, which gives the district a portion of the proceeds from the sale of that used cooking oil to use for teachers and classroom resources.
Letchworth says their ultimate goal is to eventually have all their buses running on biodiesel.