Diesel exhaust contains more than forty hazardous air pollutants, twenty-one of which are identified by the EPA as known or suspected carcinogens. These include benzene, formaldehyde, acetaldehyde and 1,3 butadiene. Exposure to diesel exhaust has been proven to cause asthma and exacerbate its symptoms, and recent studies link exposure to diesel exhaust with the development of lung and other cancers as well as heart disease. Most health experts agree that there is no safe level of exposure to diesel exhaust.

Exhaust from idling school buses can enter the vehicles through open windows and through doors during the loading and unloading process. The amount of exhaust entering buses depends on how many buses are queued up one behind the other, how long they idle and whether the proximity of building or overhang helps to trap diesel fumes. The exhaust may also enter the school building through open doors and windows or through air ventilation systems.

"No-Idling" policies should not be confused with "reduced idling" policies which permit the idling of buses for two, three or five minutes. These types of policies are difficult to enforce and completely ineffective at protecting children's health.

Effective "No-Idling" policies prohibit idling except in emergencies or during extreme weather. The policies are easy to establish, have no implementation cost, reduce greenhouse gas emissions, reduce fuel consumption and improve air quality. This is a true "win-win" situation.

View a sample "No Idling" policy.

Resources:

Grassroots Environmental Education has produced a short documentary DVD about diesel exhaust and "No-Idling" policies as part of its ChildSafe School initiative. The site also has sample policies, Q&A Sheets and scientific abstracts.