Unfortunately, there are a lot of problematic places- Hotels have “signature scents” (less so in Europe and Asia but you have to ask) and running through the duty free perfume at the airport is not so much fun. Malls are usually full of scent. Going to concerts and shows are difficult. Air “fresheners” in taxis. Lawn mowers, power boats. The best you can do is make family and friends aware of how sick you become so that they can spread the word to other guests and eliminate scented candles etc. Good luck. It’s hard