Cleaning up school buses

More than 24 million children nationwide ride a bus to and from school every day, and the majority of those buses are running on diesel.  The exhaust dirties the air both inside and outside of the school bus.  Diesel exhaust from school buses idling in line seeps into the buses through open windows and doors, exposing both the children on the buses and children waiting to board.  Engines are designed to vent some crankcase emissions to the air, which means the driver, and then the passengers, get hit with the pollution.  Diesel exhaust can also get into school ventilation systems and through open school windows causing poor indoor air quality.

Fine particulates from school buses and other sources are a health concern for everyone, but children are more susceptible to air pollution problems because they breathe 50 percent more air per pound of body weight than do adults.  There is no known safe exposure to diesel exhaust for children.  According to a study of diesel exhaust inside school buses, done by NRDC and U.C. Berkeley School of Public Health, a student sitting in the back of a school bus with the windows closed receives an average exposure to diesel exhaust that is up to 4 times greater than a child riding in a passenger car immediately ahead of the same bus.

So what’s being done to tackle the problem?

The Pittsburgh Healthy School Bus Fund

Funding provided by the Heinz Endowments and the PA DEP for this project has enabled school bus companies serving Pittsburgh Public Schools to retrofit more than fifty buses with diesel particulate filters (DPFs) and closed crankcase ventilation systems (CCVs), greatly reducing children’s exposure to diesel exhaust.

“Cleaner bus air in pipeline for schoolchildren,” Pittsburgh Tribune-Review, February 18, 2009.

In 2009, Pittsburgh Public Schools included diesel emission reduction requirements in their school bus contracts

“Parents, Environmentalists Want Buses Retrofitted,” WDUQ News, March 16, 2009.

The contracts had four key sections to reduce these dangerous emissions:

• 85% of each company’s fleet must be equipped with a DPF, either through retrofitting or by purchasing a newer, cleaner bus by the end of the five year contract.
• 100% of each company’s fleet must have CCVs by the end of the five year contract.  These CCVs prevent dangerous fumes from entering the cabin of the bus.
• Starting in the 2010 school year, preference for the after school, midday, and field trip work will be given to companies that have a higher percentage of their fleet retrofitted.
• The school district is allowing two extra years of use (from 10 years to 12 years) for buses that are equipped with DPFs.