Humidifiers: Different Types and How They Can Be A Health Hazard

What humidifiers do
Differences in humidifiers
Hazards associated with humidifiers
Preventing humidifier problems

What Humidifiers Do

Humidifiers are used in homes to increase the humidity level. Though it is important to keep humidity levels below 60 percent in a home to discourage dust mites and mold, there are also problems if humidity levels fall below 40 percent. Some of the problems that may be seen with air that is too dry (such as in the winter with furnace heating) include:

• Physical discomforts such as dry nose, throat, lips and skin
  

• Static electricity
  

• Peeling wallpaper
  

• Cracks in paint and furniture
  

• Infections from bacteria and viruses that thrive in dry air

Differences in Humidifiers

There are different types of humidifiers. They include:

• Central humidifiers: These are built into the home heating and air-conditioning systems. They are the most effective since they humidify the entire house and are less likely to be the source of humidifier-associated problems if they are properly maintained.

• Portable humidifiers: There are two kinds of these. One kind is a console humidifier that is encased in a cabinet. The second is a smaller unit that holds about one to two gallons. Both of these are designed to be used in a single room. There are several different types of these. They include:

  • Ultrasonic: These create a cool mist by means of ultrasonic sound vibrations. These use little electricity but can create white dust.

  • "Cool mist" or impeller: These produce a cool mist by means of a high speed-rotating disk.
    
    Ultrasonic and cool mist humidifiers are usually the ones that disperse the most microorganisms and minerals.

  • Evaporative: These units blow air through moistened materials such as a filter or wick to get moisture into the air. These produce the greatest amount of mist, up to 13 gallons a day. Be sure to choose one with a tank housing and wick that are antibacterial.

  • Steam vaporizer: These create steam by heating water. Since the water boils in this unit, most microorganisms are killed, but it can also be a hazard if put in a place where children or pets may knock it over and burn themselves or others.

  • Warm mist: This is a steam vaporizer that uses a cooler airflow for safety. These use a lot of electricity.
    
    Evaporative humidifiers and steam vaporizers do not usually disperse minerals into the air like the ultrasonic and cool mist humidifiers can.

Choose a unit that best meets your needs and climate. For example, a new, airtight 2000 sq. ft. home may need about five gallons per day. A draftier home may need about 10 gallon per day.

Hazards Associated with Humidifiers

If humidifiers are not properly maintained, there can be problems associated with their use. These include:

• Bacteria and fungi: These can grow in the tanks of portable and console humidifiers and get into the air by way of the mist where it can be breathed in. One bacterium in particular, Legionella pneumophila, is a concern since it is the cause of Legionnaires' disease. Health problems caused by these organisms range from flu-like symptoms to serious infection.
  
  Other bacteria found in humidifiers that can cause major health problems are called thermophilic actinomycetes. These bacteria thrive at temperatures of 113°-140°F and have been associated with humidifier fever as well as hypersensitivity pneumonitis, which is an inflammation of the lungs.
  
  The young, the elderly, and those people with lung diseases or respiratory allergies may be particularly at risk to airborne pollutants like bacteria and fungi.
  
  In order to tell if bacterial or fungal contamination may be a problem, look for a film or scum on the water surface, on the sides or bottom of the tank, or on exposed motor parts. That might indicate that bacteria or fungi are present. In addition, bacteria or fungi may grow on any crusty scale that may form in the tank.

• White dust: This is from minerals in the water. These minerals may be released in the mist of the humidifier and settle as fine white dust that may be small enough to enter the lungs. The health effects of this dust would depend on the types and amounts of minerals in the water. Though the US government does not know if these minerals will cause any serious health problems, one should still be safe and use water with a lower mineral content and follow the manufacturer's recommendation for keeping your humidifier clean.

Preventing Humidifier Problems

• Clean your humidifier daily: Clean dialy to prevent the growth of bacteria, fungi and scale. Be sure to completely empty it and wipe all surfaces dry before you refill it. For Console humidifiers, follow the manufacturer's instructions for changing water in them. Be sure you unplug the humidifier from the electrical socket before emptying it and refilling it.

• Use distilled water: The health impact of humidifiers depends a lot on the quality of water used in it. About 90 percent of compounds dissolved in water, including lead, aluminum, and asbestos, may be spewed by ultrasonic humidifiers as small particles that may result in chronic (long-term) respiratory problems. To prevent that, use distilled water in your humidifier to reduce the mineral content in the mist because distillation is the best way of removing minerals from water. Do not use tap water because it has a high mineral content?especially if you have well water. Even though distilled water may still contain some mineral content, it will probably have fewer minerals than tap water. It is important to know that not all bottled water has had the mineral taken out of it. For example, spring water, artesian water, and mineral water still contain these minerals that can lead to scale build-up and white dust.

• Use demineralization cartridges or filters: Use filters if they are supplied or recommended for use with your humidifier. Be sure to change them regularly during heating season when you are using your humidifier more. Since it is not known how effective these cartridges or filters are in removing minerals, keep an eye out for white dust that would show that the minerals are not being removed. If your water has a high mineral content, it might be cheaper to use distilled water than to use these filters.

• Drain, clean, and thoroughly dry your humidifier before you store it. Store it in a dry location. Before you use it again, be sure to clean it and wipe off any dust.

• Clean your room humidifier well and often during the heating season, usually every third day. Follow the manufacturer's suggested cleaning methods. Some manufacturers recommend using diluted household bleach for cleaning and maintenance,usually a solution of ½ cup of bleach to 1 gallon of water. Be sure to rinse the humidifier well several times to remove all traces of the bleach. If you don't, you might accidentally end up breathing in some of the chemical.

• Use a brush or other scrubber to clean the tank. Be careful not to damage the motor or to scratch the inner surface. Clean or replace sponge filters or belts when needed.

• If there are no specific recommendations on how to clean your unit, clean all surfaces with a three percent solution of hydrogen peroxide. Be sure to rinse the tank out thoroughly before using.

• For central humidifiers mounted on the furnace, be sure to follow the manufacturer's directions for cleaning and maintenance. Be sure not to allow water to stand in the tank for long periods and keep that water clean.

• Keep steam vaporizer humidifiers out of the reach of children since the steam and boiling water may cause burns.

• Buy a hygrometer to monitor interior humidity levels. Use only the amount of moisture you need. Some humidifiers contain a built-in humidistat that may be adjusted to the proper moisture level. If water condenses on windows, walls, or pictures, you should relocate the humidifier, lower its humidistat setting, or reduce its use.

• Do not let the area around the humidifier get damp or wet. If dampness occurs, turn the humidifier down so not as much mist is coming out. If this cannot be done, then just use the humidifier every so often. In addition, you do not want things like carpeting, drapes, or tablecloths, to become damp since that could lead to mold growth.

• If you start having any health problems that you or your doctor think might be caused by your humidifier, quit using it, even if you have been following directions in cleaning it.