Keeping Indoor Air Clean

Remember the first time you looked at a drop of drinking water under a microscope in Bio class and saw the millions of tiny organisms it contained? Well, the air in your home is also filled with life. Most of it is harmless. But for people who suffer from asthma and allergies, all of those little bits of dust, dander, pollen, mold and, yes, microscopic life—collectively called allergens—can be a problem. What's more, these allergens have a penchant for gathering in your home.
Some homeowners undertake extreme measures to deal with air-quality issues in their homes. Many of these efforts are unnecessary and ineffective, says Dr. David Cugell, Bazley Professor of Pulmonary Diseases at Northwestern University Medical School and consultant to the American Lung Association. But there are a number of ways you can reduce the quantity of allergens in your home. The ones we'll show you are easy to do and don't cost much.
Keeping It Clean
Decreasing the amount of dust in your home is the single most important thing you can do to control allergens. Because dust is sticky, it attracts and holds dust mites, pet hair and dander, mold and mildew. It also settles on floors and furniture, so you should concentrate on cleaning exposed horizontal surfaces.
Effective vacuuming. While they are good at picking up dirt and dust, many vacuums don't hold onto the finer particles—they just redistribute them. Try this simple test: Vacuum an area in direct sunlight and then step back and look at the machine. The sunlight will let you see how much dust is coming from the vacuum. If there's a lot, consider a new model with special bags or filters that trap microscopic particles from major manufacturers like Hoover, Eureka and Oreck. Prices of these "low-emitting" vacuums are dropping; some are available in the $200 range. The most effective vacuums use HEPA (high-efficiency particulate-arresting) filters, although even these can't trap all allergens.
Because you spend much of your time in the bedroom, pay special attention to cleaning these areas of the house. Don't forget to vacuum the registers of a forced-air heating and cooling system as well as inside closets. Try to vacuum and dust when family members who are sensitive to dust are not at home.
Carpet concerns. Wall-to-wall carpeting and rugs are a haven for dust and animal allergens. Frequent vacuuming will decrease their carrying ability; some rugs can be washed. If it comes down to a choice between carpeting and wood flooring, remember that bare wood floors accumulate only 10 percent the amount of allergens as carpeting. A compromise: Bare flooring with washable area rugs.
This doesn't mean you should automatically rip up existing carpet; experts are divided about the benefits of removing carpeting for those who are not afflicted with serious asthma or allergies. Carpeting installed without a moisture barrier directly over concrete, however, is a different case. The carpet pulls moisture from the slab, creating a petri dish for mold, mildew and bacteria.
Discouraging mites. While vacuuming and dusting at least once a week help with dust allergens, they don't kill dust mites. To keep them under control, place mattresses, box springs and pillows in plastic cases and cover the zipper with tape. Wash bed linens and stuffed toys weekly in 130°F water; wash all bedding and fabric window treatments once a month. Use a meat thermometer to determine the temperature of your wash water. If it isn't hot enough, set the water heater higher. All items should be dried in a dryer or in direct sun.
Decreasing fumes. If someone in your household is sensitive to fumes and odors produced by household cleaners, paints, pesticides or gardening supplies, store these products in sealed containers in well-ventilated nonliving areas, like a garage. Also be sure they aren't stored near return-air ducts so fumes aren't pulled into other areas. Try to buy small amounts of these products so there's less remaining around the house. Better yet, eliminate what you can and switch to unscented, nontoxic or natural alternatives for products (including cosmetics) you must use. For example, use cedar chips instead of mothballs with paradichlorobenzene.
The particulates contained in smoke are serious irritants to everyone. Consider making smokers take their habit outside, and for the sake of sensitive individuals, avoid wood fires in the fireplace and aromatherapy candles.
The simple act of removing your shoes before entering your home will also decrease the amount of pesticide, garden fertilizer, mold and pollen you track into the house.

Clean Indoor Air Sites
American Lung Association
Clean Air Org
EPA Indoor Air Quality
Green Guide
Partnership for Clean Indoor Air
Peak Pure Air
NPR Article