Medical experts as well as the federal Environmental Protection Agency agree that an air purifier won't alleviate carbon monoxide, viruses, and dust mites. While capable air purifiers can trap dust, smoke particles, pollen, and pet dander, you can reduce all of those allergens without opening your wallet. Here are some low- and no-cost steps to follow before buying an air purifier:


ELIMINATE CAUSES

Remove or reduce pollution sources. Ban indoor smoking. Avoid candles, incense, air fresheners, wood-burning fires, and scented cleaners. Vacuum often, using a low-emissions machine (See our latest vacuum cleaners report). Keep dust-sensitive people out of the area when vacuuming. Don't get pets if you're allergic; if you already have them, keep them out of the bedroom.

Minimize dust mites. Encase pillows (as shown above, left), mattresses, and box springs in mite-proof covers. Wash laundry in the hottest water you can. Avoid carpeting and other furnishings that accumulate dust and harbor mites.

Control harmful gases. Test for radon with a kit (about $15). Minimize carbon-monoxide risks; don't idle cars or fuel-burning equipment in garages or basements. Don't store or use chemicals, solvents, glues, or pesticides in the house.


VENTILATE ROOMS

Open windows and doors. Do both based on weather and outdoor air quality.

Use outdoor-venting fans. Putting these fans in the kitchen, bathroom, and laundry areas helps expel combustion gases, odors, and excessive moisture, which can breed mold and other allergens.

Vent heating equipment and appliances properly. This includes maintaining heating equipment, chimneys, and vents to properly remove combustion gases such as carbon monoxide from indoors. Install carbon-monoxide alarms (available to subscribers).