"Idling school buses spew tons of exhaust into the air, putting children at risk when they leave school at the end of each day. In New York City alone, idling vehicles emit as much pollution as nine million diesel trucks driving from the Bronx to Staten Island. But the city's laws requiring them to shut down their engines in school zones are poorly enforced."
"Idling School Buses Spew Black Carbon, Fine Particles"
Source: EHN, 10/29/2009