Most homes built in the past few decades have improper ventilation and updated homes are no better.
Weather-sealing and insulation create the dead air space necessary for weather-proofing to keep energy costs at a minimum.
Thus, we trap a lot different fumes in a home: cleaning supplies, fragrances to mask odors, the lingering “new-smell” from items bought, tobacco smoke, cooking odors and materials used to maintain/repair a home.
Some folks fear potential allergies.
Afraid of disease, some habitually wear a mask.
These things weaken one’s immune system and when a real threat comes along, they have no immunity built up to oppose it.
Homes need fresh air.
