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Q. We have tenants whose children seem to have allergies. They have pets but feel that replacing all the carpeting in the home will remedy the problem they’re experiencing. We noticed that Stanley Steamer products are AAFA certified about 98% of dog dander and 92% of dust mites. Do you believe that cleaning the carpet is sufficient, or should we replace all of the carpeting in the home in order to be sure it is not causing the allergy problem?

A. This is a challenging question, as there are many variables that may determine the effectiveness of this carpet cleaning in resolving the childrens’ symptoms.

Numerous studies have demonstrated the benefits of strict environmental control in patients with asthma and allergies.  However, other studies have produced conflicting results.  This may be because allergen levels were not reduced enough to benefit the patient.  Another possibility is that the patients studied may have been allergic to more than one thing, and reducing exposure to just one allergen was not sufficient to decrease allergy symptoms.

The type of carpet in the home will impact the results of cleaning.  Different types of carpet are easier to clean than others.  In a study of cat allergen in carpets, the carpets that were easiest to clean were short, low-pile carpets made of high density, low surface area fibers, and coated in fluorocarbon The study did not examine dust mite allergen, but it is likely the type of carpet will also impact the removal of this allergen.

If the children are pet allergic and have a pet, cleaning the carpet will have little effect on the total amount of pet allergen present in the home. Pet allergens are also found in bedding and furniture, are constantly being produced by the pets.

Many patients in the U. S. are allergic to more than one allergen. Even if the carpet cleaning were to remove a large amount of one allergen, the allergy sufferer may not feel relief because carpet cleaning has not impacted their other allergens.

The family should consult the childrens’ allergist for an evaluation, and to discuss management and treatment options.

Q. A few months back, I heard an allergist on television talking about ionic air filters being toxic to the lungs. I have had these air filters for a few years in every room, and have COPD caused by allergies. I'd like to get more information about what problems these air filters can cause, since I certainly don't need anymore problems with my lungs.


These are not really air filters. They are usually advertised as clean air machines or air purifiers. The ionization changes the charge on the particle and it sticks to the next thing it comes into contact with. There is usually not enough air flow to effectively filter many particles, so they provide minimal benefit as air cleaners. The health risk comes from the ozone they produce, which is toxic to the nose and lungs.

The Environmental Protection Agency (EPA) has additional information about this topic, which you may find useful.

The better option is to use a HEPA room air cleaner rated with a Clean Air Delivery Rate (CADR) for the size room you are using it in. For central air cleaning, a furnace filter with a MERV rating of 11 or 12 will help filter the particles blown through heating and air conditioning system.