Idle (of an engine): run slowly while disconnected from a load or out of gear.
Idle: without purpose or effect, pointless.
Of the many environmental faux pas I have observed (and been guilty of) over recent years, the foremost is an escalation of motorists who choose to idle their car engines, in the comfort of their climate controlled vehicle… eating their lunch, communicating or reading on their “devices” in parking lots, in long lines waiting for food, gas and coffee, etc.
I’m aware there are legitimate reasons — pets, children, seniors, etc. — but when there are times when it’s not that hot, you can find shade and sit with the windows open. I came from a pre-air conditioner era, so I know it’s possible to rewind our polluting ways and survive. (Car exhaust emits a wide range of gases and solid matter, causing global warming, acid rain and harming the environment and human health).
Just pay attention. And while we’re at it, turn off the water while brushing our teeth. Water and air — precious commodities!