i didn't have worse or better allergies growing up in a rural area, just different ones...i've found when i'm in rural areas i tend to react more strongly/quickly to dust, dirt, animal hair, etc. and have fewer problems with things like fragrances and chemicals (which i associate with car pollution, being indoors, or in an urban environment). i'm always allergic to dust and dander, but the allergies are way worse at my friend's house who lives down a dirt road in the middle of nowhere or at my sister's - the town i grew up in is near a peanut factory and even though i'm not really allergic to peanuts, the dust from the peanut factory causes my sinuses to go nuts and my eyes to swell up.
i think compromising can be a really good thing
in many native cultures, smudging is a really important practice and it involves fragrant plants and smoke which can be triggering for folks with mcs. i was organizing a scent-free healing justice practice space at amc last year and one of the compromises we ended up having was to have the native healers smudge outside, away from where the massage/reiki/acupuncture area was.