Molds like a warm, moist environment and will flourish in damp conditions. You may even want to use a dehumidifier to dry out moisture. Change the filters on your furnace and air conditioner monthly. This will help minimize molds and fungi in your house. Remove all carpeting in the house.
Dust mites are one of the biggest indoor culprits.
The best way to prevent dust mites is to remove all carpeting in the house, especially the bedroom and rooms you use most. Wear a mask when vacuuming. This will help prevent the inhaling of stirred up mites. Wash linens weekly in hot water . Encase pillows and mattresses in mite-proof coverings.