Best Way to Improve Air-Quality with Air Filtering Units and Ionizers

Air-filtering units and ionizers are sometimes promoted as being helpful to people with allergies. While research shows that air-filtering units fitted with HEPA filters may help asthma symptoms if they are used with anti-mite bedding covers, there is no evidence that ionizers reduce allergic symptoms. Dehumidifiers and air-conditioning units may be helpful in certain situ­ations, but humidifiers are likely to cause problems for those with allergies.

Air-filtering units

These units work by trapping pollutants as air is drawn by a fan through special filters. These units were originally designed for removing pollutants, such as tobacco smoke, from small, localized areas -such as you might find in an office reception area, where the general background noise would mask the sound of the filtering unit.

There is some doubt concerning the effectiveness of these units in removing mite allergen, but this is probably because of the type of filters used. Research shows that if fitted with HEPA filters they do improve the symptoms of mite-sensitive asthma when used together with anti-mite bedding. However it is vital to concen­trate on controlling mites by removing carpets and improving ventilation, and on measures that make sure that there is less dust in the air.

If you are interested in an air-filtering unit, opt for the model with the most powerful fan and an HEPA filter. Other factors to consider when buying a unit include how noisy it is when operating and how often you have to change filters.

Dehumidifiers

The way dehumidifiers work is by cooling air so that excess humidity condenses into a container, to be emptied either automatically or manually. Whole-house dehumidifiers are available that claim to reduce relative humidity in the home to below 50 percent. If true, they are likely to have an effect on mould growth and mite numbers. In summer however the heat given out by a dehumidifier can make the house too warm, so that air conditioning is also needed.

Smaller units may be helpful in drying out a flooded or newly plastered room, but are unlikely to play a major role in improving air quality.

Humidifiers

These units add moisture to the air Since normal human activity produces a lot of water vapour, it is usually unwise to put extra humidity into the air From a health point of view, too dry is usually better than too humid. People sometimes complain that the air dries out when the central heating is on. However this is because the relative humidity has been lowered and not because the central heating has removed moisture from the air Using a humidifier may make the air feel more comfortable, but you will be providing more favourable conditions for mould and dust mites. Try setting your central heating to a lower temperature instead.

In addition, humidifiers contain a reservoir of standing water which can become the breeding ground for bacteria and mould. Even if the unit has been designed to kill these microorganisms, dead allergenic mould may still be blown out along with the humidified air

Humidifiers can be used to help medical conditions, such as croup, but steam inhalation is as effective. If a child with asthma is having breathing problems at night, the cause should be sought and dealt with by your doctor

Air-conditioning units

Most domestic air-conditioning systems, including stand-alone units, simply cool and recirculate the air within the area they operate; they do not necessarily bring fresh air in from outside. This is not always realized -because stand-alone air conditioners are often mounted through a window, people assume that they exchange interior with exterior air as part of their operation. In fact, window mount­ing is simply the easiest method of exhausting the heat they take from inside the home.

Stand-alone units do not usually have any air filters, while filters provided for central air-conditioning systems are primarily designed to protect the cooling unit, and need upgrading if they are to be of any benefit to allergy sufferers.

Regular maintenance of stand-alone units (and the ductwork of central systems) prevents a build-up of dust and contamination by mould and bacteria – running the unit for 30 minutes after turning off the cooling function helps to dry out the system and prevent mould growth.

Air conditioning may benefit pollen sufferers, as windows can be kept closed during peak pollen times. Air conditioning also helps to reduce relative humidity, so helping to control dust mite numbers and mould growth.