Follow my advice at your own risk. Like probably almost all (if not all) advice, none of this advice (or ideas/suggestions/etc), may be good advice for everyone, or even anyone. Some of these things I do, some of them I don't do but probably should. What can I say? I'm not Gandhi. (You can google 'gandhi stop eating sugar' if you didn't get that last reference.) Anyway, I don't think it's always immoral to tell people to do things if you're not doing them yourself, but it's probably a good way to piss people off. I'm also not a doctor, but I also don't think it's always immoral for people without credentials to give advice. Still, I suggest you take my advice (and the advice of others, even professionals) with a grain of salt.
Most, if not all, of these ideas probably aren't my own. I mean, I probably got them from other people.
I don't think copying others is always immoral. Actually, I think all laws should be abolished, especially copyright laws and patent laws.
Many of the suggestions below may also be ways to practice minimalism or to keep things simple. Some of these suggestions you might find pretty austere, but they're for your own good. :-P Just kidding. Well actually, they are for your own good, and for the good of others, but if you don't want to follow certain suggestions, there may still be other ways to improve indoor air quality (IAQ). For example, if you don't want to give up wearing perfumes or colognes, you could at least follow the suggestion to "buy (or make your own) products with healthy organic ingredients".
I don't include any evidence or reasons that these suggestions may help improve IAQ, but if you want to find some, you could search the web. For example, you could google 'fabric softeners indoor air quality' to find evidence and reasons that using fabric softeners hurts IAQ.
Here are some ways to improve IAQ:
Keep your windows open
Use air purifiers
Buy (or make your own) products with healthy organic ingredients
Don't use deodorants, or at least use unscented ones
Don't use perfumes or colognes
Don't use air fresheners
Even using essential oil diffusers may be unhealthy
Don't use fabric softeners, dryer sheets, or fabric conditioners
Don't have pets
Don't burn things
Don't use wood-burning or gas fireplaces
Don't smoke, vape, etc, even pure organic cannabis or tobacco
Don't burn candles (especially scented ones) or incense
Don't burn or char your food when cooking it
Keep cooking to a minimum
When cooking, use range hoods and open windows
Don't spray for insects
When showering, turn on the bathroom exhaust fan
Don't use rugs, even in bathrooms
Choose clothing, furniture, bedding, curtains, etc made of organic natural fibers (instead of synthetic fibers)
Wipe down surfaces
Wash bedding, drapes, etc
Vacuum regularly with a HEPA vacuum cleaner
Regularly clean or replace the filters of your vacuums, air purifiers, and air conditioners
For your home:
Follow the National Healthy Housing Standard (NHHS)