Here’s my trial and error:
Yes air rooms for a little time each day
Sceptical of houseplants making any scent difference hut they do look nice
be careful about putting loads of chemicals into the air with sprays, long term you could irritate your lungs - indoor air pollution is a thing. Especially relevant to homes with babies, children and elderly adults in
change bedclothes regularly
Don’t keep old bedding materials going on for years like pillows and duvets, try to recycle those somehow- local dog rescue shelters might want used but clean duvets for their animals.
Don’t have damp bathmats in bathrooms smelling pre mouldy- hang them up each time to dry- as with wet towels
If you have drain smells then you have to call a plumber to fix the source. For lots of reasons, poor drains with standing stale water will affect your health eventually. Dont pour Zolflora down the drains to kill the environment, its not going to solve your drain problem and will cost you a lot to use. If you want to put something down your drain then try boiling water.
Clean your kitchen surfaces like walls and underneath hanging cupboards very regularly. You are trying to wipe off the residual amount of oil and food dispersal that naturally gets into the air and sits on the walls when you cook- and then those deposits in turn hold on to the smells that are released from cooking over time. Hot water on cloths important. Again be careful with your lungs with cleaning sprays.
As well as being careful buying and using strong cleaning chemicals, be very careful about what household cleaners you mix together. Don’t ever mix for example, household bleach + white vinegar in a cleaning situation. This produces chlorine gas and is very dangerous (!). More mixing examples here to avoid:
https://www.urmc.rochester.edu/MediaLibraries/URMCMedia/environmental-health-sciences-center/COEC/documents/bad-chemical-combos.pdf
Dogs will always smell, but people expect this so they’ll deal with it or avoid it. Have a dog bed or at least don’t let your dog lie directly on your soft furnishings because you can’t ever wash dog smell from the sofa. Use a thick blanket for them to lie on and wash that. If you have indoor cats keep on top of emptying litter tray several times a day.
keep your trainers and sweaty shoes near the door so they get air and not tucked away in a cupboard. If your trainers get wet and stay wet they will smell awful so be vigilant about that with drying them.
Wash sports kits promptly- put them in the machine ready to be washed as soon as they’re in the house, ideally.