What are the cautions for car diffusers?
Avoid oils that could make you drowsy: You need to exercise some caution with car diffusers. Certain scents should be avoided while driving, especially clary sage, sweet marjoram, chamomile and sandalwood. For more details on what oils to diffuse in the car see Essential oils for Driving
Don’t block your vision: Another caution is not to hang anything from the rear view mirror or anywhere else where it may interfere with vision. This is especially true of metallic or reflective objects (like a stainless steel diffuser necklace). In some areas, hanging something from your rear view mirror is illegal.
Limit diffusion time in closed spaces: What makes diffusion generally so safe is that the oils are dispersed into a large volume of air in the room. In a car, we have a small closed space. Therefore, using a diffuser that sends out a constant mist into a small area for a prolonged time is not recommended. An ideal car diffuser should be able to be unplugged, turned off, or put away. If that isn’t possible and you are driving for longer than 30 minutes, you may want to give yourself a break from the scent by opening the windows.