The Toxic Threat Lurking in School Buses

States are moving to replace old vehicles that expose children to high levels of diesel exhaust.

(Photo: Karen Lynnie/Getty Images)

Feb 5, 2015· 1 MIN READ
Padma Nagappan is a multimedia journalist who writes about the environment, renewable energy, sustainability, agriculture, and biotechnology.

We’ve all inhaled sickening exhaust fumes when driving behind a diesel school bus. But those fumes can also get sucked inside the bus, exposing children to high levels of pollution.

Riding ini such “leaky” older school buses can lead to respiratory illnesses and even cancer, which is why the Utah legislature is considering legislation to replace 450 of the worst-polluting buses in its 2,500-vehicle fleet.

“Our school community said we had to do something about our dirty school buses if we want to solve our ambient air problem,” said Rep. Steve Handy, R-Utah, who hopes new buses can hit the road by the fall.

Handy is also pushing for $40 million to not just replace the worst-polluting buses but also to destroy them, so they’re not sold to school districts in other states.

Across the U.S., thousands of older diesel school buses ply the roads, exposing unsuspecting schoolchildren to concentrated levels of diesel exhaust.

In California, the state Air Resources Board replaced more than 1,000 school buses and retrofitted 3,500 with $200 million in bond funding.

Colorado, Maine, Montana, Texas, and Vermont are among other states that have also taken moves to replace school buses.

One option is to equip buses with diesel particulate filters to reduce children’s exposure to pollution. That’s cheaper than replacing diesel buses with vehicles that run on cleaner propane or compressed natural gas.

In California, the Air Resources Board sponsored studies that spurred the state to act.

“Once California and other states realized the importance of replacing or retrofitting old diesel school buses, they made it more of a funding priority,” said Scott Fruin, an author of one of the studies who is now at the University of Southern California. “California went from one of the oldest and dirtiest school bus fleets to one of the cleanest in the space of just a few years.”

Replacing the buses has a double benefit, pointed out Julian Marshall, who led the a University of California, Berkeley, study: “Unlike with other vehicles, it’s not just people outside the bus—also the ones inside—that are impacted by the fumes.”

“The same discussion happening now in Utah has happened or will happen across the country,” Marshall said. “We know that replacing the buses will clean up the air inside and outside, and the health benefits far outweigh the costs.”

While states weigh funding issues, the study authors suggest they look at interim measures that cost nothing but will benefit children and the public.

“We recommend they use the cleanest buses on the longest routes, reduce idling time and don’t allow buses to leave the schools in the afternoon in a long continuous line, fumigating the students with exhaust,” said Arthur Winer, an environmental professor emeritus at the University of California, Los Angeles. “Even if there is no funding or political will to replace or retrofit school buses, these are measures states could take.”