Are you experiencing intermittent allery symptoms?
Are allergy symptons at home that seem to disappear when you leave your home? Perhaps you have mold spores in your air vents.
Mold commonly occurs when there is moisture in your air ducts. From a scorching hot day when moisture in the air condenses inside your vents to air borne mold spores, if you are experiencing fluctuating allergy symptoms you should consider having your air ducts inspected.