Carpet and Health

Scientific Studies

German Allergy and Asthma Society Study

Smooth flooring or wall-to-wall carpet?  So far, the answer has divided allergy patients, doctors and scientists into two camps.  The Canadian Carpet Institute who speaks for the Canadian carpet industry, has been repeating it high and low, for a long time:

Carpet traps particles(dust, pollen, and other allergenic substances) in its fibres, thereby keeping them out of the breathing zone until the carpet’s “trapping” qualities are refreshed by efficient vacuuming.  On a hard surface (ceramic, hardwood, vinyl, etc.), these particles are constantly swirled up to find themselves in the breathing zone.

A study commissioned by the DAAB (die Deutscher Allergie- und Asthmabund e.V. – the German Allergy and Asthma Society) in 2005 shows that using smooth flooring markedly increases the risk of finding an increased fine dust load in indoor rooms, while using “fitted” (wall-to-wall) carpets minimizes this risk.  The results of this study were presented to the public in Düsseldorf at the DAAB Conference in June 2005.

The study has shown that the average fine dust concentration in indoor rooms equipped with smooth flooring material much higher than in indoor rooms covered with wall-to-wall carpets, and thus exceeds the limit value.

With 62.9 µg/m³, the arithmetic mean value of the fine dust concentration in rooms with smooth flooring clearly exceeds the limit value of 50 µg/m³, whereas in households with fitted carpets, the mean value amounts to 30.4 µg/m³ and is thus substantially lower than the limit value.

Fine dust is a big problem, especially for allergy patients.  Irrespective of the kind of dust inhaled, the particles as such, with their mechanical effect, cause irritation when they enter the respiratory tract.  Where the bronchial system has previous damage, this effect will be so much the stronger.  Moreover, we find other pollutants bound to these particles, e.g., allergens that, in this manner, may get deep down into the lungs where relevant reactions may be caused.

Above all, for particularly sensitive persons already suffering from previous damage to their airways, the selection of a flooring material – like carpet – binding dust and not emitting it to the air to be breathed is an essential preventive aspect.

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Carpets and Allergies in Sweden

Claims in Sweden that textile floor coverings cause allergic reactions in some people have not been adequately proved, according to two Swedish scientists.

There were intensive discussions and reports in Sweden in the seventies claiming that carpet was the source of harmful contaminants, resulting in allergic reactions.  As a result, Swedish consumers and public building officials severely reduced their use of carpet.

In 1996, Professors Roshan L. Shishoo and Alf Börjesson, of the Swedish Institute for Fibre Polymer Research, pointed out in several publications that the occurrence of allergic reactions and other environmental sensitivity in the general population had increased.  They reported that carpets constituted only a small proportion of the total floor covering market in Sweden, having fallen from a market share of 40 percent in the mid-seventies to only 2 percent in 1992.

Professors Shishoo and Börjesson argued that the removal and decline of carpet usage did not mean improved conditions for allergic patients.  On the contrary, they missed the advantages of carpet such as comfort, insulation, and noise reduction.

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European Community Respiratory Health Service Study

In 2002, a major international survey of over 19,000 people in 18 countries showed categorically that people who have carpet in their home, especially in the bedroom, have less incidence of asthma.

The full study was published in the Journal of Allergy and Clinical Immunology 110(2): 285-292 (2002).

The European Community Respiratory Health Service (ECRHS), an international multi-centre epidemiological organization, conducted a study on the prevalence of asthma and its known or suspected risk factors.  The study was designed to investigate the association between asthma and housing dampness, mould exposure and house dust mite levels.

Questionnaire data was examined from 19,218 subjects from 38 centres in 18 countries including Europe (Belgium, Denmark, Estonia, France, Germany, Iceland, Ireland, Italy, The Netherlands, Norway, Spain, Sweden, Switzerland, and the United Kingdom) as well as Australia, India, New Zealand and the United States.  The questionnaire was led by an interviewer who collected information on respiratory symptoms and on environmental and lifestyle factors.

The questionnaire also asked for information on housing characteristics including home age and type, type of heating and ventilation systems, presence of double glazing, type of floor covering in the bedroom and living room, as well as any water damage in the house in the last 12 months, water in the basement in the last 12 months and whether there was any mould or mildew on any surface inside the home in the past 12 months.

The association of these factor and asthma (based on symptoms in the past 12 months) and bronchia responsiveness (by methacholine challenge) were evaluated.  Odd ratios were obtained and adjusted within study centres for sex, age, and smoking status.

Results of the Study

The results of the study showed that in homes that had fitted (wall to wall) carpets and rugs in the bedroom, there were fewer asthma symptoms and less bronchial responsiveness (Odds Ratio range 0.69 – 9.91).  This effect was consistent across study centres.  It was more pronounced among dust mite antigen sensitized individuals.  Reported mould exposure was associated with asthma symptoms and bronchia responsiveness (Odds Ratio range, 1.13 – 1.33).

In centres with a higher prevalence of asthma, the prevalence of reported indoor mould exposure was also high for both asthmatic subjects and non-asthmatic subjects.  The study showed that, whereas indoor mould growth has an adverse effect on adult asthma, the use of carpet and/or rugs, especially in the bedroom, had a positive affect on people.  In addition, those who were known to be sensitive to dust mites had an even better response when carpets were used.

The authors of the study investigated the affect of fitted carpets and rugs in the bedroom on asthma in more detail.  They found a consistent negative association between the presence of carpets, rugs, or both in the bedroom, and current asthma.  There was no evidence for different associations in centres where bedroom carpeting is more or less common.

Analysis were done after separating specifically for dust mite sensitization to evaluate the possible modifying effect of house dust mite allergy on the relationship between bedroom carpeting and asthma. Odds Ratios for all health outcomes measured were lower among individuals who were sensitive to house dust mites.

The difference was statistically significant for bronchial responsiveness, with the protective effect of having any textile floor covering being stronger among mite-sensitized subjects than among non-sensitized individuals.


The negative association between textile flooring and asthma was more pronounced for the bedroom than the living room.  This negative relationship between bedroom carpets and asthma appeared in almost all study centres, including those countries where fitted carpets are uncommon and countries with a low prevalence of house dust mite sensitization.

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New Jersey Study

Carpet the bedroom and don’t miss school!

In a study of over 4,600 school children in the New Jersey area started in 1999, it was found that when a child’s bedroom was carpeted, there were lower rates of asthma medication being used and lower school absenteeism.

The full study was published in the Journal of Exposure Analysis and Environmental Epidemiology, Vol. 13, No. 3, 169-176 (2003).

The Study

In the region of Passaic, New Jersey, the Passaic Asthma Reduction Effort (PARE), a 4-year screening program was developed by the Passaic Beth Israel Hospital in co-ordination with public, private, and parochial schools.  The area is predominantly Hispanic and asthma prevalence is significantly higher in African- and Hispanic-American communities than in other populations.  Asthma has been getting steadily worse amongst the population, including an increase in mortality rates.  In addition, asthma is also the major cause of school absenteeism in the US.

Three Hispanic groups predominate in this community: Dominicans, Mexicans and Puerto Ricans.  Most of the analyses were conducted on these three groups only.  Of the potential 6,480 elementary children to be screened, parental questionnaires were returned for 4,634 children.  The overall questionnaire responses identified 75% of children as Hispanic, with 10.5% and 5% as black and Asian children, respectively.

The survey was designed to help physicians identify environmental triggers for children to enable them to design individualized asthma treatment plans.

The Questionnaire

The two points of interest in the study were asthma diagnosis and school absenteeism.  Each child was asked five questions about whether anyone smoked at home and, if so, who; whether they had pets and, if so, what they were; and whether they had a rug or carpet in their bedroom.

Parents were also requested to complete a questionnaire about their child’s respiratory health, family history of asthma, school absenteeism, potential environmental exposures in the home, insurance status and race/ethnicity.

Environmental factors in the questionnaire included exposure to tobacco smoke; mildew/mould in various areas of the home; carpeting in the child’s bedroom; the presence of furry pets; pet access to the child’s bedroom; use of feather pillows; presence of roaches; and the use of pesticides in the home.

The Results

Among children diagnosed with asthma, medication use was low.  It was found that across all 4 years, the two major factors associated with asthma diagnosis were exposure to tobacco smoke in the home and dampness/mould in the bathroom.

The study showed that feather pillows and carpeting in the child’s room had no statistical association with asthma diagnosis for the children in this study.  The study also showed that where there was carpeting in the child’s bedroom, there were corresponding lower rates of asthma medication use and lower school absenteeism.  For preschool children, damp bathrooms and mould were the only household factors associated with asthma diagnosis in the children studied.

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