Nerf-style Tear Gas Delivery System

My nephew has these tennis racquet shaped air ...guns(?)that are operated by pulling back on a piece of stretchy rubber attached to the racquet frame, aiming it at somebody, and releasing. They are surprisingly effective at a distance of up to 30 feet -- a serious blast of air; enough to make you start, especially if you aren't aware that someone is shooting you until it hits you. Through experimentation, we discovered that they could be used to deliver certain noxious gasses, at a distance, to unprepared targets with spectacular results.

This design could be adapted to deliver tear gas to individuals in crowds, specifically, those being violent. Just arm several police officers with these cheap toys, put a puff of pepper spray or tear gas into each, and deliver appropriately.