Recent research has found that air inside homes can be more polluted than the air in the largest, most industrialized cities. Indoor air pollution is caused by a lack of ventilation and can lead to more frequent colds, respiratory problems, and other ailments and diseases. Keep the house clean. House dust mites, pollens, animal dander, and other pollutants can be reduced through regular cleaning. Install and use fans vented to the outdoors in kitchens, bathrooms, and laundry rooms. Keeping humidity levels in these areas below 50% can prevent water condensation on building materials, which can breed bacteria and mold. High levels of mold can be incredibly dangerous to your family’s long-term health.