Ask the Expert
For: Clearing Up the Sinusitis Mystery, January 2002
Q: Will a humidifier
help prevent colds in the winter?
W.C., VIA THE INTERNET
A: It's hard to say. Dry air can irritate your nasal passages and throat, possibly making them more susceptible to infection. And if you already have a cold, dry air dries mucus and makes it more difficult to clear from your body. That's why steam or moist air is useful when you're congested and sick—to help loosen mucus. Colds are caused by viruses, however, and humidity does not get rid of them.
Studies show that people who live in damp houses have higher rates of respiratory problems, including infections and asthma. High humidity can, for instance, increase levels of molds in a house, which can cause cold-like symptoms. Water damage, poorly ventilated bathrooms and kitchens, and appliances such as humidifiers, air conditioners, and even dehumidifiers (if not emptied) can add excessive moisture. Keep the relative humidity level in your home around 50% (measured by simple devices called hygrometers, available at hardware stores for about $10).
Humidifiers do help some people breathe better when the air is cold and dry. But when improperly cleaned and maintained, humidifiers can actually be a breeding ground for many microorganisms, which can lead to infections, asthma symptoms, and allergies. Follow the manufacturer's cleaning instructions, which usually require emptying the water from the tank daily. Wipe the tank clean, and replace with fresh water. Every one or two weeks, disinfect the tank using a mixture of one teaspoon of chlorine bleach to one gallon of water. Allow this to sit for 20 minutes before thoroughly rinsing with a 50% solution of vinegar—this should eliminate mold.
UC Berkeley Wellness Letter, December 2001
