What is a diffuser aroma? A diffuser aroma or "diffuser oil" is the liquid scent that goes into an diffuser in order for it to emit scent. While most companies use aroma chemicals, we use only pure plant-derived essential oils. Ajne expertly blends them to a perfect consistency for aroma diffusion, while capturing a unique "Scents of Place." Each is 100% natural, petroleum free, anti-bacterial and anti-fungal. We invite you to view our unmatched selection.