The Environmental Protection Agency's Clean School Bus USA initiative is a voluntary program that seeks to reduce children's exposure to diesel exhaust and the amount of air pollution created by diesel school buses. They will to do this by eliminating unnecessary bus idling, retrofitting buses with better technologies and/or using cleaner fuels, and replacing the oldest buses with new, less-polluting buses.
Realizing these alternatives can be costly to schools, funding is available to assist schools through the EPA's regional offices. A map on their site allows you to identify your state's regional office and their contact information. You can also check their site to see which school districts are already participating in your state. Funding is also available to assist states in implementing diesel emission reduction programs.
Beyond the environmental impact, why does the Clean School Bus USA initiative matter? A study from the National Resources Defense Council and the Coalition for Clean Air found that children riding a diesel school bus may be exposed to up to 4 times more toxic diesel exhaust. This level of exposure "pose(s) from 23 to 46 times the cancer risk level considered significant under federal law." Diesel exhaust can also exacerbate asthma and other respiratory illnesses. Children are the most vulnerable to the toxic effects of diesel exhaust and air pollution because they breathe 50% more air per body weight than adults.
If you are a parent, grandparent, school board member, school employee, or concerned citizen you should encourage your school district to voluntarily become involved in the Clean School Bus USA initiative.