There are several types of essential oil diffusers on the market today. The most common type is the vented vial diffuser. This vented type is typically used in the home by people who wish to keep a supply of essential oils available whenever they need them. The disadvantage of this type of diffuser is that if the air that the essential oil passes through is very dry, then it can cause a burning sensation in the person inhaling it. The vapor produced in a vented diffuser should not contain any excess moisture. It should also be kept away from direct sunlight because it may evaporate if it is exposed to direct sunlight.