The fastest-and cheapest-way to cut down on air pollution is to prevent school buses and parents from idling in the pick-up and drop-off lanes. Vehicle exhaust is a huge source of smog emissions and particulate pollution; diesel buses emit some 40 hazardous air pollutants. By some estimates, you can burn as much gas idling for a mere 10 seconds as you would restarting the engine-so make school a no idle zone.