There is another reason to avoid fresheners and diffused scents - especially if oil based. Given enough time, the oil can coat the air sacs in your lungs and make it difficult to breathe.
My SIL used mineral oil to moisturize the area around her nose for years. Then, breathing difficulties set in. Drs did a zillion tests, finally they took a biopsy of her lungs and found the air sacs were coated with oil.
They told her that she may improve her lung function over time if she stops using the mineral oil. Her response? "But I need it!"
The DR told her that using it would kill her, so she doesn't need it. That made her think about what he said.
Please be careful when using fresheners and diffused oil scents. Your long term health may depend on it.