May 6th Proclaimed “Stop School Bus Idling” Day

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Hotline, Summer 2003

by Rachel Filippini, GASP Executive Assistant

In an effort to raise awareness about the deleterious effects of school bus diesel exhaust on human and environmental health, and particularly the link between diesel exhaust and asthma, GASP proposed that Allegheny County Council proclaim May 6th “Stop School Bus Idling” Day, which they did on April 15th 2003. Please see a copy of the proclamation on page 3. GASP was also featured in the Pittsburgh Post-Gazette article “Clearing the Air” available at

In the United States, about 4.8 million children under the age of 18 are estimated to have asthma, a disease of the lungs. That is one in every 15 kids. Asthma is the leading cause of childhood hospitalization, long-term illness, and school absenteeism, accounting for more than 14 million missed school days, nationally, each year. Pennsylvania has the third highest number of children with asthma in the country. Many environmental factors can trigger an asthma attack, including dust, pollen, animal hair, roaches, mold, smoke — from burning wood, coal, gas or cigarettes, smog and last but not of least concern, diesel exhaust.

Diesel exhaust is a mixture containing over 450 different components, including vapors and fine particles. Over 40 chemicals in diesel exhaust are considered toxic air contaminants by the State of California. Diesel exhaust has been linked in numerous scientific studies to cancer, the exacerbation of asthma and other respiratory diseases. In fact, the fine particulates found in diesel exhaust not only aggravate asthma, but may actually cause asthma in otherwise healthy people, according to a new study conducted by researchers at the Natural Resources Defense Council (NRDC) and the University of California at San Francisco School of Medicine. Fine particulates from 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, especially those with asthma or other chronic respiratory disease. 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.

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 tailpipe 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. Diesel exhaust can also get into school ventilation systems and through open school windows causing poor indoor air quality.

Idling school buses also waste a lot of fuel. A typical diesel vehicle burns approximately one gallon of diesel fuel for each hour it idles. This can really add up for a fleet of buses over the course of a school year. A short amount of idling time is necessary for starting up school buses, to properly warm up engines and build pressure in the air brakes. School bus manufacturers generally recommend 3-5 minutes warm-up time, according to the Environmental Protection Agency. Additional idling times may be necessary in winter to allow heaters to warm the buses before students board. GASP is concerned about unnecessary idling, such as occurs when buses arrive early, before school lets out, and idle in front of the school for 15-20 minutes or more.

GASP started tackling this enormous problem by writing to more than 300 schools in Allegheny County and to all 43 superintendents, educating them about the issue and asking that they take part in “Stop School Bus Idling” Day. GASP received a variety of calls from school districts who wanted more information about retrofits and how to set-up a “no unnecessary idling” policy at their school. Taking part in the day is just the first step; next GASP would like to see schools set up their own idling guidelines and seriously consider using retrofits and/or purchasing alternatively fueled cleaner buses. To learn more about retrofits, alternatives and possible funding opportunities, contact GASP at (412) 441-6650 or

Next on the horizon, GASP would like to see a county-wide “no unnecessary idling” policy, and we are working with the County Council to make this a reality. Stay Tuned!