Air-Cleaner Shortcomings For Asthmatics

While air purifiers sound like a great idea, they are really the products of last resort. The best defense against air pollution will always be source control and ventilation. If your home is jammed with flowering potted plants, perhaps it would be in your best interest to put those plants outside rather than buy an expensive air cleaner. Air cleaners can make a difference, but they are not perfect. They can lose efficiency as their filters, precipitators, or sorbents become saturated with pollutants. Equally concerning, as a filter captures more and more pollutants and becomes saturated, the filter itself may begin to deliver harmful gasses, odors, and particles into the air. This means you must pay meticulous attention to recommended maintenance and filter changes.

 

As for odors, while activated carbon removes many odors, most machines cannot remove every odor. Avoid air cleaners that "scent" the air, making it smell "fresh." Scenting only replaces one odor with another and does nothing to remove harmful fumes. Also, stay away from products that make ozone, a reactive gas known to trigger asthma. Finally, some asthmatics are sensitive to formaldehyde found in building materials like particleboard. Particleboard maybe used in small appliances like air cleaners and should be avoided.

 

The limitations of air-cleaning technology were examined in 1997 by an ad hoc committee of air-cleaner manufacturers, who met at the request of the US Food and Drug Administration. According to the commission, "the data presently available are inadequate to establish the utility of these devices in the prevention and treatment of allergic respiratory disease." The committee went on to conclude that "air-cleaning devices should only be considered if symptoms remain severe despite other avoidance measures and there is reason to believe that a significant load of airborne allergens is present." Likewise, studies in the scientific literature offer mixed results. One study on air filtration found that while there was a "trend" toward higher peak flows and a reduction in airborne pollutants, no difference in subjective symptoms or bronchial reactivity was demonstrated. Bottom line: Source control and ventilation will do more to clean your air than any air cleaner; air cleaners are the refuge of last resort.

 

Let's examine in more detail why air cleaners are only a small part of the asthma solution. For an air cleaner to work, irritants must be airborne so they can enter the cleaning unit and be filtered. The problem is that most asthma triggers, like dander, are rarely airborne; they are usually trapped in the carpet, furniture, or bedding. These irritants travel into your airway when you disrupt them—such as by sitting on a piece of furniture, making the bed, or walking on or vacuuming the carpet—thereby causing them to become airborne. This is why experts recommend excluding carpeting, drapes, and other textiles from the homes of asthmatics and allergy sufferers. It is also the reason why source control is your best hope of relief; if you can eliminate an irritant at its source, you don't have to worry about that allergen getting into your bedding, carpeting, furniture, or lungs.