The National Bureau of Standards states that air filtered by a HEPA unit is free of 99.97 percent of all contaminating particles. Air conditioners and humidifiers are very beneficial during the appropriate season, but they also collect mold and can cause problems if they are not cleaned regularly. Mold grows in damp and humid areas such as basements, bathrooms, closets, attics. Check the house for damp areas that might conceal molds. Throw out all old or unused newspapers, books, magazines, clothing and articles that are sources of mold and mildew.
Allergic persons are often supersensitive to odors that can trigger an attack at any time.
Scented fabric softeners and laundry detergents are especially irritating. Encase mattresses, box springs and pillows in allergy-proof covers. Use sheets, pillowcases, mattress pads, and bedspreads made of 100 percent washable cotton or cotton flannel, free of chemical finishes. Buy special non-allergenic pillows, or those filled with Dacron or polyester, not kapok, down or feathers. Air bedclothes outside in sunny weather.