Did you guys smoke though?
No.
Unless we're counting herbs.
I just developed allergies to everything. Getting married and then moving into a house that had been closed up for few years, had a mildew problem, a bad furnace, and 40+ yr old carpeting finally did me in. All the chemicals I inhaled trying to clean and fix it up didn't help. Even gutting it 5+ years later and starting new only made a little improvement.
Since I've moved into mom's old house though, I've seen a really big improvement. The basement has always been dry, there's a built in air cleaner, and not a ton of carpet (I will be eliminating even more hopefully next year). Neighbor has COPD and did away with all her carpet except for one room, going with area rugs and laminate...big difference in her health, and I can tell the difference walking in.