The exhaust fumes smell "like old gas," says 17-year-old Adam.

"It just smells like old tar," adds 17-year-old Stevie. "You know how they make tar on the roadwork, and something like that? It really stinks very bad."

Both Adam and Stevie ride the bus to school every day, and because of that, according to the NRDC study, they may be exposed to four times more toxic fumes compared to the exhaust that collects inside a car. According to the study, a kid who rides the bus every school day for ten years may be exposed to 46 times the cancer risk considered 'significant' under federal law.

So what should kids do?

"Short term, the air in the buses is cleaner when the windows are open. So parents and school districts and bus drivers should know that weather permitting, it's better to keep the windows open," says Dr. Howard Frumkin, the chairman of environmental and occupational health at Emory University.

Also, bus drivers and parents should encourage kids to sit toward the front, because exhaust fumes tend to collect in the back of the bus, he says.

Or, use the potential cancer risk as just one more reason to avoid the bus altogether.

"If a child can walk to school or bike to school rather than ride the bus, that's terrific for lots of reasons," says Dr. Frumkin. "It's good exercise for children. And our kids need exercise these days."

By Sally Atwood
CWK Network

A study of air quality inside school buses found that children riding on school buses may be exposed to four times the amount of toxic diesel exhaust than someone riding in a car directly in front of it.

Researchers from The Natural Resources Defense Council (NRDC), along with the U.C. Berkeley School of Public Health and the Coalition for Clean Air continuously took air quality samples inside the front and back of 4 school buses over a 20-hour period. In addition, they sampled the air quality outside the bus and in a passenger car traveling ahead of the bus. They found that diesel exhaust levels on the buses were 23 to 46 times higher than levels considered to be a significant cancer risk according to the U.S. Environmental Protection Agency.

Some of the many different chemicals, gases, and particles that are found in diesel exhaust have been shown to be harmful to people. Long term exposure to diesel exhaust is linked with lung cancer, decreased lung function and premature death, according to the NRDC. In addition, studies show a correlation between diesel exhaust and asthma attacks in children.

Children are particularly susceptible to the harmful effects of diesel exhaust and other air pollutants. This is due, in part, to children's:

• Faster breathing rate
  
• Breathing through their mouths
  
• Spending more time playing outdoors

According to the NRDC, the majority of the nearly half a million school buses in this country, which carry more than 23 million children to and from school every day, still use diesel fuel. Age of the bus and quality of maintenance can affect the levels of exhaust inside the bus. However, any level of exposure to diesel exhaust is unacceptable. The NRDC report urges school districts to replace diesel school buses with alternative fuel school buses.

Levels of diesel exhaust inside buses are highest when the windows are closed, according to the NRDC study. Also, when the windows are closed, exhaust accumulates in the back of the bus.

• Whenever possible, school bus windows should stay open.
  
• Children should sit toward the front of the bus whenever possible. In particular, children with the longest bus ride should sit toward the front of the bus.

Should you keep your child off the bus altogether? The NRDC points out that health risks from diesel exhaust are related to the number of years of exposure. They say there is generally no need for children to stop riding school buses right away unless a child has asthma or other respiratory problems that seem to worsen while riding on a school bus.

Emory University www.emory.edu
Natural Resources Defense Council www.nrdc.org
Southeast Pediatric Environmental Health Specialty Unit at Emory University www.sph.emory.edu/pehsu