Diffusers used for Aromatherapy.
Several styles are available.
Some use electricity and a small fan, others a heating element or small lit candle under a bowl of water. Atomizers use a small pump and specialized glass to disperse the molecules into the air in a fine mist. Other diffusers are made to place a few drops of oil on and slowly disperse the essential oils into the air. And don't forget your Automobile. When you use a diffuser for extended periods of time, remember your sense of smell will become accustomed to the essential oils and you may not 'smell' them.