Smell things that aren't there?

My mother says the air in our house is bad. Neither I nor anyone else smells anything. She says she has symptoms like a dry throat, a coated tongue, etc. She's already gotten several devices and tried various scented candles and other fragrance diffusers. We've also had professionals come out, and they haven't noticed anything unusual. She's smoking less these days, though. I've heard that menopause can also change your sense of smell, but could that really be true? Please help!! 🙏🏼