I agree air fresheners are pretty horrible things, so I guess either you get away from her or you try to negotiate some kind of compromise. If she's the type to listen to reason, you might try arguing on health and safety grounds. Opinions range from "small amounts are harmless" to "they're a strong and avoidable risk to your health." To my mind, the logic is that there's no great need to regularly use something that the industry churns out, and you can't really trust the free market to keep you safe, especially if they're using unnatural chemicals. You might also mention that you have an aversion to them, and liken it to a strong dislike of certain foods, something that isn't an attitude, it comes to us unbidden.
If you have less trouble with natural fragrant gases, there might be an acceptable substitute out there, such as crushing a few lavender flowers. They used to sell an air filter that removed stinks quite well, but it's a long time since I saw one that was unscented. To my mind, if they have to spray scent around, it's a sign that they haven't managed to remove the original bad odour in the first place.