Day in and day out, children across the U.S. are riding to school on aging buses, breathing what some activists say is a dangerous brew of pollutants up to five times dirtier than the air outside.

It is a situation that Congress and many states have sought to fix in recent years. In fact, in 2005 federal lawmakers passed a measure to replace or retrofit the dirtiest diesel engines across the nation, but little has been done.

Around the country, state officials are struggling to find the money to carry out clean school bus initiatives, and Congress has yet to deliver on the $1 billion it promised over five years to help states clean up diesel fleets, including school buses.

Read (AP via MSNBC)