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New Hampshire Department of Environmental Services
PUBLIC GOVERNMENT BUSINESS A to Z LIST

Overview
Air pollution from diesel vehicles has health implications for everyone, but children are more susceptible to this pollution because their respiratory systems are not fully developed. Diesel exhaust typically contains particulate matter (PM), hydrocarbons (HC), and carbon monoxide (CO). Exposure to fine particles in school bus exhaust can result in increased frequency of childhood diseases, such as asthma. For more information, see the report Children's Exposure to Diesel Exhaust on School Buses.

At schoolyards, idling school buses release emissions directly into the breathing zone of children. Children are exposed to the emissions at the most concentrated levels as they line up to board an idling bus. Limiting the amount of idling time not only reduces exposure of school students to the harmful pollutants in diesel exhaust, but it also improves air quality.

The US Environmental Protection Agency created a program to address emissions from school buses called the Clean School Bus USA Program. Suggested options for controlling emissions from school buses include implementing anti-idling programs and installing retrofits on buses. Retrofitting buses with pollution control devices can produce significant results. For example, installation of diesel oxidation catalysts can reduce emissions of particulate matter (PM) by 20 percent and emissions of hydrocarbons (HC) by 50 percent. Installation of diesel particulate matter filters can reduce emissions of PM, HC, and CO by 60 percent to 90 percent.

In 2002, DES teamed up with the New Hampshire School Transportation Association (NHSTA) to launch a voluntary initiative to protect school children and bus drivers from excessive exposure to exhaust emissions from school buses. As part of the initiative, fleet managers and school bus drivers throughout New Hampshire adopted policies and practices to reduce school bus engine idling time whenever possible.

In January 2011 a state law went into effect that directs school boards to “… address methods of minimizing or eliminating emissions from buses … taking into account the state anti-idling and clean air zone policies established by the department of environmental services.” Chapt. 200:48 Air Quality in Schools.
DES and NHSTA have developed numerous materials to assist schools and transit providers in developing these policies, which can be found under “Publications” on this webpage.

School bus drivers can make a significant impact on their health and that of their passengers by limiting engine idling whenever possible. Reducing idling also saves fuel, reduces engine wear and tear, and saves school bus companies and school districts thousands of dollars each year.




NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
(603) 271-3503 | TDD Access: Relay NH 1-800-735-2964 | Hours: M-F, 8am-4pm

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