A look at the airflow from a common computer style fan. It's easy to look at the fan and think that the air just flows straight through it, but in reality the spinning impellers creating a spiral vortex of air. This can be a nuisance in some applications like a silk flame where the air has to flow parallel to the silk. But the vortex effect is actually useful in other applications because it tends to create a very turbulent air pattern that wraps around surfaces as it flows past them.
When a common tealight candle is placed on the top of the fan the flame stays lit, but swirls with increasing vigour as the airflow is increased. Quite a neat effect in its own right.
When a bottle of "air freshener" (chemical aroma) with wick is placed in the fan, the airflow wraps round the bottle and wick and dissipates the aroma into the room quickly. This could be used as a simple multi-aroma selection arrangement, with several fans and bottles being activated in sequence.