School buses travel approximately four billion miles each year, and more than 25 million students ride a school bus every day. These buses provide the safest transportation for getting children to and from school.

Unnecessary school bus idling affects human health, pollutes the air, wastes fuel, and causes excess engine wear. Fortunately, it's easy to implement practices that reduce school bus idling.

Human Health Impacts:
Diesel exhaust from excessive idling can affect human health. Diesel exhaust contains significant levels of particles, known as fine particulate matter, which are so small that several thousand of them could fit on the period at the end of this sentence. These fine particles pose a significant health risk because they can pass through the nose and throat and lodge in the lungs, causing lung damage and premature death.

People with existing heart or lung disease, asthma, bronchitis or other respiratory problems are most sensitive to the health effects of fine particles. The elderly and children are also at risk. Children are more susceptible to air pollution than healthy adults because their respiratory systems are still developing and they have a faster breathing rate.

Air Pollution:
Idling school buses can pollute air in and around the bus. Exhaust from buses can also enter school buildings through air intakes, doors, and open windows. Diesel exhaust contains pollutants that contribute to ozone formation, haze, acid rain, and global climate change.

Wasted Fuel and Money:
Idling buses waste fuel and money. When idling, a typical school bus engine burns about half a gallon of fuel per hour. School districts that eliminate unnecessary idling can have significant savings in fuel costs each year. Use the Fuel Savings Calculator to estimate the fuel and money saved by reducing idling in your school bus fleet.

Engine Wear-and-Tear:
School bus engines do not need to idle for extended periods to warm up. Engine manufacturers generally recommend no more than three to five minutes of idling.

What Schools Can Do:
Everyone has a role in reducing emissions from school buses.

School Officials

Bus Drivers



Content courtesy of US EPA Clean School Bus Program


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