I have lavender oil in a diffuser in my office to keep everyone calm and peaceful.
My diffuser/atomizer is from Natural Grocer. It’s a conical shaped thing about 5 or so inches at its base. It uses a tiny sound emitting/vibrating little metal disc in the center of the bottom of the water holding part. The sound vibrations break the water into fog. Not heat.
Then I have a 3.5” elbow of PVC I put on top of the top of the cone and that goes into a 1.5’ length of PVC pipe that ends about 4-5” from where my face is as I sleep.