Say you find yourself in a setting where you’re breathing one nasty allergen after another. You can’t leave the room or remove the source. Perhaps you can't even open a window – it's 10 degrees outside, or the window is bolted shut. Enter the face mask. Lightweight, cotton surgical masks strain out particles such as pollen, dust and smoke.

For chemical vapors you may need a charcoal filtered mask. Perhaps you’ll only have to wear a mask in special situations, such as sitting in a meeting where everyone is smoking. Or you have a whole stack of papers to photocopy and can’t tolerate the copier fumes.

Faces masks are lifesavers, too, when the outside air is particularly bad, says Phyllis Saifer, M.D., an allergist in Berkeley, California. Again, charcoal filtered masks work best. ”Granted, other people are puff off by seeing someone wearing a mask, especially if you sit next of them on the bus or the subway.

But a mask can make the difference between feeling ill and feeling well. Just don't walk into a bank wearing a mask,” add Dr. Saifer. ”That makes people really edgy.” For your own home or office – wherever you spend a considerable part of your day – it's worth looking into more elaborate equipment for ways of reconditioning the air you breathe.

Humidifiers and dehumidifiers. People with asthma and other respiratory allergies fell better when they breathe moist air – it keeps the nose and bronchial passages from drying out. Cold dry air is also irritating to airways, which are already exceptionally sensitive in people with asthma.

When the heat is turned on for the winter, you may need a humidifier. Too high humidity in the house, however, promotes growth of house dust mites, molds and fungi, and tends to carry more dust and pollen – all contributors to allergy and asthma. So in summer, you may need a dehumidifier.

Indoor humidity of about 35 to 50 percent seems to strike a balance between personal comfort and preventing proliferation of allergens around the house. Be sure to get equipment with a humidistat that automatically shuts off when the desirable level of moisture is reached.

And allergy doctors recommend that portable humidifiers and dehumidifiers be kept clean and mold free by cleaning them frequently with a stiff brush rather than by adding strong disinfectants and detergents to the water. Air to air heat exchanger.

As we said before, too tight buildings with poor ventilation are a major cause of chemical fume buildup and mold growth. Air to air exchangers help solve the problem without sacrificing fuel efficiency. They work on the principle of ”good air in, bad air out.” Warm, outgoing indoor air and cold, fresh incoming air pass through ducts with a common wall.

Heat from the indoor air is transferred to the fresher outdoor air. Should you have a heat exchange system installed, be sure that the outside air intakes are positioned where the air the freshest – not drawing fumes from the garage or kitchen stove exhaust from your own or other buildings.