Schools put brakes on bus pollution.

Christopher Gagnon is a first-grader at Pembroke Elementary School in Birmingham. Most days, like most first-graders across the country, he rides a bus between home and school.

Christohper loves riding the bus, but often he's not too keen on its smell. "It just kind of, like, stinks," he said recently. Sometimes he's seen other kids near the back holding their noses.

In fact, fumes from school buses are a lot more unhealthy than fumes from most cars.

About a year ago, Birmingham school officials began taking steps to fix that problem. They are among thousands of school administrators across the country who want to clean up air pollution from school buses.

The first step: Ask school bus drivers not to idle their buses for more than three minutes. Idling a bus means leaving the engine running without going anywhere. In the past, many school buses have idled while the drivers were waiting for kids to get out of school. That was especially true in winter, when drivers may have kept the engines on to keep the buses warm.

In the past year or so, the federal government has been telling educators that fumes from school buses are more unhealthy than fumes from most cars. Studies have shown that unhealthy fumes can build up inside school buses. The government doesn't want anyone to hear about these studies and panic. There is no need to stop riding school buses because of the fumes.

Still, the Environmental Protection Agency in Washington, D.C., has a new Clean School Bus program to teach educators, parents and kids how to cut down on unnecessary pollution from school buses. That's important because millions of kids from around the country ride school buses. Kids are more sensitive to pollution than most adults.