Cleaner School Buses Full Speed Ahead

What's so important that over 24 million kids have to have it every day? Here are some clues: it's big, it's yellow, and it travels 4 billion miles a year. School buses! Though this integral part of schooling is the most reliable and safest means of transportation for kids, there is something we can do to make them even safer.

The majority of the nation's 450,000 school buses run on diesel fuel, which emits high amounts of particulate matter (PM), hydrocarbons (HCs), carbon monoxide (CO), nitrogen oxides (NOx), and toxics. With proper emission controls or use of alternative fuels, harmful emissions from these buses can be significantly reduced.

Wisconsin Partners for Clean Air expressed a concern over this issue and the Department of Natural Resources obtained funding in 2004 to retrofit school buses in southeast Wisconsin. But what is a retrofit? A retrofit is a device or method that allows a vehicle to run cleaner. This can be a device placed on the vehicle (e.g. on the exhaust system) or a cleaner fuel. The majority of the retrofit devices used in our program are called diesel oxidation catalysts, which is a combination of a muffler and catalytic converter-type device that reduces HCs, CO, and PM in diesel tailpipe exhaust by 20-50%. These devices are virtually maintenance-free and have no impact on fuel consumption or vehicle performance. Other devices installed under this program include crankcase filters, which reduce emissions under the hood, and partial particulate filters, which are similar to an oxidation catalyst but with a different catalyst structure that trap more pollutants.

The project was funded with a federal Congestion Mitigation and Air Quality (CMAQ) grant from the Wisconsin Department of Transportation. This program expanded through 2010 to include not only school buses, but municipal and off-road equipment as well from a total of 26 fleets. During the project 935 school buses and municipal equipment were retrofitted with over 1,000 devices! These grants were only available to ozone non-attainment areas and used in the following counties: Door, Kenosha, Kewaunee, Manitowoc, Milwaukee, Ozaukee, Racine, Sheboygan, Washington, and Waukesha.

The federal grant had a 20% match requirement. We raised over $22,000 through donations mainly from businesses, including WPCA members, DNR and EPA employees. Organizations also contributed by gathering support and donations through newsletter articles and notifying their members at meetings.

Though this project specifically targeted school bus fleets and municipal equipment, there were ways that everyone could participate.

The school bus retrofit project was a win/win for everyone. Bus companies got cleaner buses for free, and everyone gets to breathe cleaner air.

For more information on school bus retrofits in general and what other states are doing, visit EPA's Clean School Bus USA web site.