Q. Starting around this time of year, many people begin using humidifiers at home to add moisture to dry air. In some cases, people at work are exposed to humidification systems during both the heating and air conditioning seasons.

Are there any health risks associated with the use of humidifiers? If so, what are the symptoms? What can be done to keep any problems from developing?

A. There are some risks associated with using a humidifier. Although researchers aren't sure what the extent of the risk might be, it appears to be small.

The main problem with humidifiers is that the water contained in them can harbor growing bacteria and molds. These organisms can lead to several problems, including infection and allergies.

Fortunately, the types of humidifiers most people use at home release little, if any, infection-causing molds or bacteria into the air. Ultrasonic humidifiers -- the most common kind -- emit few organisms; even so, many models have built-in heaters designed to kill molds and bacteria before sending out humidified air.

However, particles of mold and bacteria can still trigger allergic reactions in susceptible people. Even dead organisms can lead to stuffy nose, sinus congestion and irritated eyes. A few people develop what's known as "humidifier fever," an allergic reaction that can mimic pneumonia.

Most reports of health problems with humidifiers involve either large units at worksites or so-called cool mist vaporizers. Much more so than home models, worksite humidifiers have been linked with allergic reactions, humidifier fever and cases of Legionnaires' disease.

Legionnaires' disease is a pneumonia caused by a germ that grows in the standing water of cooling towers and air conditioning ducts.

To prevent your chances of allergies or the small risk of infection, you should regularly clean the water container of your humidifier.

One recommended mixture is an ounce of chlorine bleach in a pint of water.

If you think you're getting allergies from using a humidifier, you could try going without it for a while and then start again to see if your symptoms appear related.

You may need to check with your doctor or an allergist to be sure.

For more information about humidifiers and their safety, see the September 1988 issue of Consumer Reports.

Jay Siwek, a family physician from Georgetown University, practices at the Fort Lincoln Family Medicine Center and Providence Hospital in Northeast Washington. Consultation is a health education column and is not a substitute for medical advice from your physician.

Send questions to Consultation, Health Section, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071. Questions cannot be answered individually.