How can people with allergies ideally control the air quality and climate in their homes?
Controlling the air quality and climate of your home may sound daunting, but it is actually not that difficult to achieve and can lead to substantial benefits. Good maintenance of these systems can increase the benefits you will receive and prolong the life-span of these devices.
HEPA Filters: HEPA stands for High Efficiency Particulate Air-filter. These devices were developed during the Apollo era of space exploration. They can filter most substances from the air, down to 0.3 microns in size. (A micron is a unit of length equivalent to 1/1000 of a millimeter.) They are helpful in filtering pollen, mold spores, animal dander, and fumes.
HEPA filters aren't for dust mites. Dust mite allergens are heavy and fall to the ground quickly, thus avoiding being trapped by HEPA filters.
It is important to remember that you can not filter the world. In other words, you need to run these filters with the windows closed. The size of the room also needs to be taken into consideration when deciding what size HEPA filter to purchase.
HEPA filters have become increasingly available in many discount home improvement stores. Previously, these devices had been primarily available through allergy supply companies and catalogs at a premium price. Now, you can do some comparative shopping before you buy. Other factors to consider before buying include the required interval between changing filters, the ease of obtaining replacement filters, and warranties. One critical factor in the use of HEPA filters is the noise level generated. Many people stop operating the unit due to the "white noise" associated with the device. Make sure that you listen to the device before you purchase it. The good news is that the newer generation of filters is much quieter.
Another type of filter is the electrostatic filter. So far, these have not been shown to be as efficient as the HEPA filter.
An important point to make here is that HEPA filters are not the ultimate solution to the problem of indoor allergens. They can help to some degree but in no way do they replace cleaning, temperature and humidity reduction, clutter removal, and avoidance of allergens such as pet dander.
Dehumidifiers & Humidifiers: Remember, house mites require high humidity to thrive. Dehumidifying the air is easily accomplished with an air conditioner, but this is practical only in hot weather. The correct placement and use of fans and vents can help reduce humidity as can a dehumidifier machine. It pays to find a knowledgeable sales source that can help you determine the appropriate size machine needed for your individual home or office. Clearly, the most important point about a dehumidifier is that it must be kept scrupulously clean. Otherwise, molds will flourish in the collection chamber making your problem worse than it was in the first place. Dehumidifiers must be cleaned daily. Some models have automatic shut off mechanisms that keep the tank from overflowing and some have a continuous drainage system.
Humidity gauges are readily available at any hardware store. A range of 40-50% humidity is good. Humidity lower than 35% can make breathing uncomfortable for some people with asthma or other respiratory conditions. Generally speaking, low humidity is not the health problem that high humidity can be.
Humidifiers are rarely needed except for children with croup. In most parts of the country, the humidity seldom drops below 35% and the nostrils and airways provide natural moisture. However, it is true that in certain parts of the country, a well heated home can become overly dry.
Croup is a viral infection in small children that is characterized by a harsh, barking cough. The condition is frequently worse at night. One of the recommended treatments is mist or steam, which is best provided by a cool air humidifier. Vaporizers should be avoided due to the risk of burns.
As previously noted, some central hot-air systems may include built-in humidifiers that can make the air more comfortable to breathe. However, there are definite problems with this type of system. Not only can these units blow mold spores and dust all through the air, but keeping these systems mold and bacteria free is extremely difficult.
Stand-alone humidifiers are available and are frequently used in homes with antiques or fine art that could be damaged from excessive dryness. They are often recommended for people with respiratory problems and eczema, which can be worsened by dryness. The truth is, though, that humidifiers tend to cause more problems than they solve. They should be used only sparingly, as their health benefits are primarily limited to infants or young children with croup.
The most frequently used stand alone unit is the evaporative humidifier. This system uses a wick or pad to absorb water from a reservoir. A fan then disperses the water vapor through the air. This method can cause bacterial counts in the air to skyrocket, leading to "humidifier fever," a flu-like infection of the respiratory tract.
Although ultrasonic humidifiers kill the bacteria, they also spray parts of the dead microorganisms into the air along with minerals that then deposit on surfaces throughout homes. A fine white dust on furniture evidences these mineral deposits. Generally, the ultrasonic models are no longer distributed but these devices are kept for years, so be sure to check what type of model you might own. A newer type of device is a vibratory humidifier that doesn't cause mineral deposits. All humidifiers should be used sparingly and MUST be cleaned after each use to prevent the rapid growth of bacteria and mold spores. Just by lowering the temperature of the home during the winter, the air will contain more moisture and the need for humidifiers will be minimized.
Air Conditioning & Heating Systems: Air conditioners are critical in filtering summertime air for patients allergic to molds and pollens. They also function as excellent dehumidifiers, thus limiting the growth of dust mites and molds. Another unexpected benefit is that the airflow discourages cockroaches since they prefer non-ventilated spaces.
Filters on both central and window units require frequent changing and or cleaning to remain efficient and prevent mold growth.
Separate room or area filtration units are more effective than whole house filtration units that are installed on central air systems. Claims that an entire house can be adequately filtered with just one unit are false. A HEPA filter can only cover a certain number of cubic feet and separate units need to be installed throughout the system.
Central air-conditioning and heating systems may also come with electrostatic filters that catch smaller particles than regular filters. The filters charge the particles in the air as they pass through the filter. The charged particles are then trapped by an oppositely charged plate in the unit. These devices must be cleaned frequently as well.
A concern about electrostatic filters has been ozone production, which can make asthma worse. This hazard has been reduced by the addition of charcoal filters.
Unfortunately, it is not clear whether the special filters available for home heating and air-conditioning units are completely effective. Be sure to inquire about the particle size that the filter is guaranteed to trap. A minimum of 5 microns is recommended. At this point, it appears that of the two options, HEPA filtration is superior.
Another option is the placement of individual filters over the outlet ducts themselves. These filters should be cleaned weekly and replaced as necessary. They are readily available from most allergy supply stores and catalogs and home hardware stores.
Some forced-air heating systems come with built-in humidifiers. This feature can backfire because dust particles are stirred up by the hot air and mold can flourish in the humidifier itself. Cleaning these units is of the utmost importance, but this can be a cumbersome task. If mold is a problem, it's probably best to have the humidifier removed.
Options apart from forced air systems include space heaters and radiant-heat systems. These two methods of heating are advantageous in that allergens and irritants are not distributed throughout the home environment as they are with forced air systems.