Would it be possible to build an 'air-lawnmower'?

By "air-lawnmower" I don't mean an imaginary lawnmower--ogous to the imaginary "air-guitar" and "air-bands". I am proposing that those noisey, polluting lawn mowers be powered by compressed air! Because a lawnmower is used for only an hour or two to complete the job, and spends most of the time unused, it lends itself to using a stored power supply such as gasoline, OR AIR! To the engineers out there I ask: Is it even feasible to have a lawnmower powered by compressed air? The weight of the air reservoir wouldn't weigh much more than a full gas tank and ociated motor. What say you?