Carpet has long been regarded as the enemy when it comes to allergies and asthma. Those living with asthma or allergy symptoms have historically been advised to remove all carpet in the home because carpet traps allergens. It is believed that this exacerbates the symptoms of these conditions. A great many reputable sources advise allergy and asthma sufferers to remove the carpeting. Even the Mayo Clinic continues to make this current recommendation:
"Carpeting can be a reservoir for allergy-causing substances (allergens) that trigger asthma. ... Hard-surface flooring such as vinyl, tile or wood is much easier to keep free of dust mites, pollen, pet dander and other allergens... Remove carpeting and use hardwood or linoleum flooring and washable area rugs. If that isn't an option, use low-pile instead of high-pile carpeting and vacuum weekly with a vacuum cleaner that has a small-particle or high-efficiency particulate air (HEPA) filter. Shampoo the carpet frequently."
However, over the last 20 years or so, some studies have challenged this view of carpeting as a problem for allergy and asthma suffers. While some of these studies are funded and promoted by the flooring industry itself, others are from reputable scientific sources and some suggest that carpeting can actually help allergy and asthma sufferers.
The Contrary Studies
Several reputable scientific studies done between 2000 and 2010 seemed to contradict the conventional wisdom regarding carpeting as a problem flooring material for those who suffer from asthma or allergies.
European Community Respiratory Health Survey
A large study of more than 19,000 people in 18 different countries was conducted, and the results published in 2002 in the Journal of Allergy and Clinical Immunology 110:285-92. In addition to several European countries, the study included data from the United States, Australia, New Zealand, and India. The study looked at the association between household characteristics such as dampness, mold exposure, and dust mite levels and asthma in adults. Their results:
Fitted carpets and rugs in the bedroom were related to fewer asthma symptoms and bronchial responsiveness.
2005 German Study
In 2005, results of a study conducted by the DAAB (German Allergy and Asthma Society) were published in the German magazine ALLERGIE konkret. The article outlined the specifics of the study, and highlighted the message that wall-to-wall carpet actually improves air quality: "The core result of the study is, however, clear: In a room with a bare floor, the risk of more airborne fine particulate rises, while the use of wall-to-wall carpeting minimizes this risk."
Most people understand that carpet holds allergens such as dust, dander, hair, etc. But instead of being a drawback, this study suggests that it can be an advantage, especially to those who are sensitive to such allergens. The argument is that carpet holds onto the allergens and does not release them into the air, thereby trapping them where they cannot be inhaled.
2008 Sauerhoff Study
Another, more recent study was published in 2008 by toxicologist Dr. Mitchell W. Sauerhoff, Ph.D., DABT, titled Carpet, Asthma, and Allergies - Myth or Reality?. Dr. Saurerhoff, according to the Carpet and Rug Institute, researched studies "encompassing scientific investigations performed in 8 different countries over a period of 19 years." His findings: "... based on the available science, carpet does not cause asthma or allergies and does not increase the incidence or severity of asthma or allergies symptoms. In fact, with respect to asthma and allergies, multiple studies have reported fewer allergy and asthma symptoms associated with carpet."
Not So Fast...
If you think these studies have put to rest the belief that carpeting is a bad flooring material for allergy and asthma sufferers, think again. In 2018, the NCBI (National Center for Biotechnology Information), in a paper published in the International Journal of Environmental Research and Public Health, performed an exhaustive review of 49 separate studies published between 1980 and 2017 on the effects of indoor carpeting on air quality and health symptoms. Most, though not all of these studies, showed both an increased presence of known allergens in rooms with carpeted floors, as well as a higher incidence of health symptoms including asthma attacks and allergies.
The majority of studies appear to find correlation between carpet floors and adverse health outcomes such as respiratory infections, asthma worsening, and age at asthma onset. We have not found peer-reviewed evidence supporting the notion that modern carpets now are unproblematic for the indoor environment. On the contrary, the literature suggests that the use of carpets is linked to increased levels of indoor dusts, allergens, and microorganisms, and associated with increased risk of a number of health outcomes including mild cognitive effects, irritative symptoms, and asthma.
What Is the Reality?
The carpet industry has argued vociferously that modern carpet materials do not have the same performance characteristics as older carpets, and no longer pose the same health risks to allergy and asthma sufferers. There may be some merit to this argument. Most recent studies, including the NCBI's summary, do acknowledge that there has not yet been sufficient examination of how different carpeting materials impact health symptoms.
But on balance, the most recent independent scientific studies still support the long-standing belief that carpeting tends to collect the dust mites and other allergens that can cause allergies and asthma symptoms. Claims that the carpeting performs a service by holding these contaminants rather than allowing them to float in the air have not bee supported—rooms with carpeting tend to have more free-floating allergens in the air than rooms with hard-surface floors.
Still, there can be considerable benefits to having carpeting as a floor covering, including its ability to muffle sound, improve the insulation value of a floor, and provide a cushioning surface that can protect against injuries from falls. Where carpeting is desired in an area used by allergy sufferers, it is best to follow the recommendations of the ACAAI (American College of Allergy, to use "low-pile carpets made of high density, low surface area fibers, and coated in fluorocarbon."
Cleaning Is Essential
Of course, some maintenance of your carpet is required to be able to truly breathe easy. Regular, thorough vacuuming of carpeting is essential in order to remove these allergens from the environment completely. For cut-pile carpets, using a vacuum with a beater bar or powerhead attachment is most effective. (Do not use a beater bar or powerhead attachment on a looped style/Berber carpet.)
Most sources also recommend periodic deep shampooing of the carpeting in homes where allergy or asthma sufferers live.
Always Seek a Physician's Advice
Your doctor is the best source of information on how a flooring material may affect your allergies or asthma symptoms. Symptoms can be caused by a wide variety of substances, ranging from simple dust to chemical compounds in the air—or even by combinations of these substances. An allergy specialist is best qualified to tell you if carpeting is likely to irritate your allergy or asthma symptoms.