There are many different kinds of diffusers, but the most popular tend to be the vaporizing/misting variety as they tend to be inexpensive. However, Aeroscena®, Ascents®' parent company and research division, has spent more than 7 years developing products specifically for clinicians to use in professional settings. Clinicians like doctors and dentists will generally not use diffusers that produce a mist, because most of these diffusers are simply not hygienic enough.
This is because misting aromatherapy systems are “open” and can therefore collect airborne bacteria. They also easily grow mold unless constantly cleaned -- distilled water must be used. Clinicians cannot risk making patients sick by blowing bacteria and mold around their offices. Misting diffusers are also prone to tipping and spilling, and use liquid oils () that require previous knowledge of aromatherapy to blend and measure into appropriate “dosages.” Professionals just don’t have the time or patience to deal with that.
Additionally, heating essential oils or mixing them with water can dilute some of their most effective properties. Heating in particular is a big problem, which is why we never recommend diffusers that work based on the warming of essential oils.
The best types of diffusers are based on ambient cold diffusion, i.e. ones that operate via a . This may seem like a simple way to go, but it’s both effective (especially for large rooms) and it doesn’t adulterate the oils or damage any of their chemical properties. It simply blows the scent through the air at fixed intervals and intensities -- truly a "set it and forget it" way to go. No cleaning, no water, no mist and no mess.