Environmental Compatibility
In theory, school buses reduce pollution in the same manner that carpooling does but on a much larger scale; a single school bus can take take as many as 90 cars off the road at one time. However, buses are not a completely pollution-free method like biking or walking. Some of the drawbacks involved stem from the idling of buses while waiting for students to be unloaded and loaded at bus stops and at school. Since most school buses use diesel fuel, people standing or walking near the bus are exposed to exhaust fumes, which are believed to lead to health problems. Some older buses have been retrofitted with upgraded emission controls and diesel particulate filters, and new buses meet more rigorous emissions standards with more advanced engines and emission control strategies such as Selective catalytic reduction; a bus meeting 2007-model year emissions standards is 60 times cleaner than a bus from 1990.
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