Every day, half a million school buses safely carry 24 million American children to school, field trips and athletic events.
Unfortunately, most buses are powered by diesel engines that actually pollute the air inside the bus. Studies show the pollution gets trapped inside the bus, where kids breathe it in.
Soot from two sources
Pollution come from emissions from the tailpipe and from the engine. Engine emissions (also referred to as crankcase emissions) enter the school bus cabin mostly through the door and the floorboard.
Because the door is right near the engine, engine emissions get sucked into the school bus, every time the door opens.
Unhealthy diesel exhaust
Diesel engines spew out nearly 40 toxic substances, smog-forming emissions and particulate matter (PM), better known as soot. Coarse and fine particles (PM10 and PM2.5) are breathed deeply into the lungs where they can lodge, creating serious, even life-threatening health problems.
Children are at particular risk because their lungs are still developing. Kids also breathe two times more air per pound of body weight than adults do. The damage to young lungs can result in reduced lung function by adulthood and other dangerous health problems.
Children receive an extra dose of pollution twice a day
Children riding buses older than 2007 models receive an extra dose of pollution on each ride: monitoring shows that the diesel pollution inside a typical school bus can be up to five times higher than the outside air.
Unless your child's school bus has been retrofitted with a filter or your child is riding on a brand new 2007 school bus, chances are, your child is breathing in unhealthy pollution levels.
Solutions are at hand
Science indicates that even short-term exposure to elevated particulate levels can have detrimental health effects. The good news is that children do not have to be exposed to diesel school bus pollution. Cost-effective solutions are available.
To cut harmful soot pollution by 90 percent, a bus can be replaced with a new 2007 engine model year bus or retrofitted with a filtering device on the tailpipe, called a diesel particulate filter (DPF).
Engine emissions can easily be eliminated with a crankcase ventilation system (CCVS). A CCVS reroutes the engine emissions to the engine air intake preventing harmful emissions from escaping into the air and the bus cabin.
Cities around the country are cleaning up school buses
Many densely populated cities have taken strides to clean up buses, from Houston to New York. Still, the majority of the half-million or so older buses in the U.S. have not been retrofitted or replaced.
Among the places that have cleaned up many old polluting school buses:
The history of clean school bus campaigns in other cities tells us that the technologies work.
Public awareness of this issue is growing. In California, Durham School Services recently settled with the Environmental Law Foundation and other nonprofit organizations and will post warnings about diesel pollution on all buses, communicate the dangers of diesel pollution to parents, and retrofit or replace all buses in their 9,000 vehicle fleet by 2014.
4 Steps to Cleaner Buses
- Replace buses with new ones
- Retrofit old buses
- Reduce Idling
- Route Efficiently