Protect children from tailpipe fumes.
Idling vehicles produce exhaust and exhaust fumes are bad for our health and bad for the environment. Diesel fumes are the worst. Vehicles that run on diesel fuel contribute a disproportionate amount of air pollution and toxic risk: specifically, oxides of nitrogen, fine particulate matter (PM 2.5 and PM 10) and air toxics. School buses that run on diesel fuel are notable polluters.
Recent scientific studies point to evidence that diesel emissions not only exacerbate asthma but that prolonged exposure can cause asthma and can set-up a propensity for asthma in the unborn. (Even ordinary car emissionsincluding but not limited to diesel exhaustcan damage the DNA of fetuses while they are still in the womb.)
Diesel is most harmful. The fine particulates of diesel fuel can bypass respiratory defense mechanisms and lodge deep in the lungs, impairing lung function. While prolonged exposure to particulate matter is a factor in reducing overall life expectancy by a few years, short-term exposure is associated with increased risk of death from heart attacks or other cardiovascular events. Diesel fumes may enhance the effects of some allergens among sensitive individuals. Children, because of their proximal relationship to diesel-powered school buses and their quick metabolisms, are at particular risk.
The Advance Respiratory Care Magazine article (below) is informative.