97% of homes have one – and no wonder! With unrivalled underfoot luxury, practically unlimited colour and design potential, carpet has long been recognised as providing that special welcome. It also has numerous practical benefits:
Choice A limitless array of colours, textures, designs and qualities. It’s a case of any colour you like with carpet!
Luxury Soft, tactile, comfortable and cosy, nothing quite matches the feel of padding around on a soft, sumptuous carpet. It is sheer luxury underfoot!
Sound Noiseless underfoot, it absorbs sound. Due to its soft cushioning properties, carpet virtually eliminates impact noise and results in a calmer, stress free environment. Properly laid carpet absorbs up to 45db resulting in a quieter life!
Soft and forgiving, carpet is non-slip and is a safe and gentle surface for feet – particularly little ones!
You don’t get cold feet with carpet! Carpet is heat retentive. 15% of all household heat disappears through uninsulated floors.
Practical, extremely robust and hard wearing, carpet doesn’t scratch, scuff or splinter!
Trouble free maintenance No need for mops and buckets – just give it a regular vacuum. Carpet is easy to clean and keeps looking good with little effort.
Hygiene Carpet acts like a filter, trapping airborne dust until it is removed by routine vacuum cleaning. With smooth floorcoverings conversely, dust is disturbed with every draught of air. The airborne dust content in carpeted rooms is significantly lower than that in rooms with smooth floorcoverings.
Health The scientific evidence shows carpet to be the ‘healthy option’.
Value for money Relatively inexpensive when compared with other consumer durables and fashion accessories, carpet is manufactured at various price points so there is something for everybody!
* This information is provided by The Carpet Foundation
WHY CARPET IS THE HEALTHY FLOORING OPTION
Article by The Carpet Foundation
Practical benefits of carpets
As well as the obvious aesthetic features carpet gives consumers a wide range of practical benefits which are often forgotten:
a.. Heat insulation – which can generate significant energy savings.
b.. Comfort and warmth – giving an incomparable luxury feel.
c.. A non slip soft surface – for safety with forgiving impact.
d.. Absorbs pollutants – for better indoor air quality.
e.. Ease of cleaning – the practical floor solution.
Carpet for Healthy Living
Claims that carpet has a major impact on asthma have no reliable scientific basis for the following reasons:
a.. No scientific studies have ever proved that the total removal of carpet on its own has ever clinically benefited asthma patients.
b.. Asthma is complex and influenced by many diverse factors including pets, genetics, diet, pollen, smoking, infections, pollution, dust mites etc.
c.. In any event dust mites thrive only in temperatures of 25°C and Relative Humidity of 70%, conditions normally found in bedding but not carpet in the UK.
d.. Airborne dust mite allergen can trigger asthma attacks when inhaled but carpet acts as a filter trapping these particles in the pile, reducing the possibility of inhalation.
e.. A study by the German Asthma and Allergy Federation (DAAB). Has shown that the air over smooth floor coverings contains, on average, 62.9 ?g/m3 of fine dust particles whilst over carpet the average is 30.4 ?g/m3. Carpet is therefore their recommended floor covering for those prone to asthma Where a significant decline in carpet use has taken place asthma cases have risen dramatically. In Sweden, where health hysteria led to a 77% reduction in carpet use over a 15 year period between 1975 and 1990 the incidence of asthma increased by over 300% in the same period.
f.. Good ventilation with temperature and humidity control will limit dust mite populations and reduce indoor allergen loads.
g.. Normal household cleaning on a regular basis with a good quality vacuum cleaner removes most allergen, dust and pollutants from carpet.
Indoor Air Quality
a.. All materials emit gasses from VOCs (Volatile Organic Compounds) but carpet emits much lower levels than other common indoor products and poses no threat to consumers. For example plywood emits twice as much VOC as carpet, wallpaper over 16 times more and paint 200 times more.
b.. Carpet acts as an absorbent for many common airborne pollutants and improves Indoor air quality.
c.. All materials used in carpet manufacturing are subject to the closest scrutiny and processes conform to the highest environmental control standards.
Carpet, like most products, needs to be looked after and the majority consumers, living in clean, tidy, well-ventilated homes vacuum their carpet regularly to prevent a build up of dust particles. In these circumstances there is no objective scientific evidence to show that carpet poses any health risk whatsoever to consumers.
The Carpet Foundation represents the premier group of British based carpet manufacturers, who between them produce over 60% of all carpets made in the UK amounting to £350million sales and with collectively more than 1000 years of carpet manufacturing experience, and more than 1100 independent retailers (Registered Specialists).
In compiling this information The Carpet Foundation has examined over 40 scientific papers and articles and has written a definitive paper on the topic, the full text of which is reproduced below.
CARPET, THE HEALTHY FLOORING OPTION
Carpet can be found in 97% of UK homes and without doubt it is the overwhelming favourite floorcovering for British consumers.
The advantages of comfort and warmth; colour, design and texture; energy and noise insulation, ease of cleaning and safety are all good reasons why consumers buy carpet with confidence.
Recent press stories promoted by environmental groups and anti-carpet organisations, funded by producers of laminate flooring, have sought to promote other floorings on the grounds that carpet is unhealthy particularly for those individuals who suffer allergic reactions. Much of this anti-carpet propaganda has concentrated on dust mites and asthma and toxic pollutants in carpet and is based on a highly selective view of existing science.
The Carpet Foundation, which represents the top carpet manufacturers in the UK accounting for over 60% of the total carpet produced in Britain and between them sharing over 1000 years of experience, has produced this detailed review of the key scientific papers covering the subject of health and floorcovering.
The review covers 42 research studies, reports and articles that illustrate the deep complexity of the subject and proves conclusively that there is no scientific validity for suggesting that carpet is a major threat to the health of consumers, even those with common allergic reactions.
For a wide range of reasons carpet remains the healthy flooring option for UK flooring consumers.
This document has been compiled with the collaboration of the European Carpet Association, GüT, (The European association for environmentally friendly carpets) Wool Research Organisation of New Zealand, Wools of New Zealand and the Carpet and Rug Institute (USA).
EXECUTIVE SUMMARY – SCIENCE IN SUPPORT OF CARPET
1.. Asthma is a very complicated condition and experts cannot agree on a single cause for the illness. Dust mite allergen is only one of the causes of sensitisation and triggers for asthma attacks which is influenced by a wide range of other factors.
2.. The main site for dust mites to live and to thrive in UK houses is in bedding and bedrooms and in overstuffed chairs and sofas.
3.. The indoor environment in UK homes is rarely suitable for large populations of dust mites to live and thrive in carpet. Temperature and humidity are frequently too low.
4.. The live dust mite does not pose a problem for asthma sufferers, but their faecal pellets contain the allergen which, on inhalation, triggers asthma attacks in sensitised individuals.
5.. The filter like properties of carpets holds allergen materials in the pile and significantly limits its potential for becoming airborne again. Hard floors allow allergen on the surface to re-circulate readily in the atmosphere through vibrations or movement of the air.
6.. Fresh air ventilation together with temperature and humidity control will significantly reduce dust mite populations and regular vacuum cleaning (with proper dust receptacles and filters) will remove most of the allergen load from the carpet.
7.. There is no scientific evidence to support the advice that the removal of carpet is clinically beneficial to asthma sufferers. No studies have ever been carried out which conclusively links a carpet free environment to clinical benefits for asthma sufferers. In fact in Sweden where health hysteria led to a 77% reduction in carpet use, there was a corresponding 300% increase in asthma in the same 15 year period to 1990
8.. All materials emit gasses from V.O.C’s. (Volatile Organic Compounds) but tests have shown that carpet emits significantly lower levels than other indoor finishes and furnishings and as such, these pose no threat to UK consumers.
9.. On the contrary wool pile carpet absorbs common gaseous airborne pollutants and generally improves indoor air quality. Carpet also traps other particulate pollutants, deposited through foot traffic or airborne settlement, holding them in the pile of the carpet, away from its surface until they can be removed by regular, normal vacuum cleaning.
10.. The manufacture of carpets in the UK is controlled by environmental legislation and manufacturers recognise their responsibility towards the environment. All process emissions have to meet stringent regulations policed by the environment agency. As with every other industry, where new evidence points to the undesirable effects of a process or chemical it is phased out to an agreed timescale. The UK carpet industry has an excellent record of compliance and improvement.
11.. It can be of no surprise that a manufactured product such as carpet will contain traces of the chemicals used in its production or the production of its raw materials. Some are applied deliberately, such as the mothproofing treatment Permethrin, and are essential for the carpet to be functional in the home. Others may be a residual, by-product or contaminant from raw material processing. In either case, the traces are minute and represent no health hazard to the consumer whatsoever. However, the industry is not standing still and is continually working to find processes and material suppliers capable of reducing or eliminating even these insignificant traces.
12.. Regular, normal vacuum cleaning and periodic carpet cleaning will significantly reduce the amount of any allergen or toxic pollutants already held safely in the carpet pile away from the surface.
13.. Carpet continues to offer consumers a wide range of practical and safety benefits
a.. heat insulation,
c.. noise absorption,
d.. ease of cleaning and maintenance
e.. obvious aesthetic benefits
f.. positive impact upon indoor air quality.
14.. The safety benefits of carpet must also be clearly recognised. Carpet is seen as beneficial in hospitals particularly those specialising in orthopaedic care where its’ non slip and cushioning properties in case of falls are particularly beneficial. Smooth floors in contrast are considered quite dangerous in this respect.
ALLERGIC REACTIONS, DUST MITES AND ASTHMA
Between 5 and 10% of the population of Western Europe in general and 6% of the UK population suffers from allergic diseases and 90% of these are sensitised to the dust mite allergen Der p1. These allergic diseases are eczema, dermatitis, hay fever, rhinitis and asthma (1). Although there has been a great deal of concern about asthma in children a recently published work shows that there is evidence that over a 10 year period ending in 1998, the rate of occurrence of asthma in the UK is on the decline and that asthma attacks are reducing in number. (2)
There are two main allergens – dust mite allergen and cat allergen, which can sensitise certain people who can subsequently have an allergic reaction when particular substances or situations are encountered. These “triggers” which give rise to allergic reactions in sensitised people include: -
Main triggers for allergic reactions (3)
Dust mite allergen
VOC.’s – Poor air quality
Cigarette smoke – Poor air quality
Cooking emissions – Poor air quality
Workplace emissions – Poor air quality
Other factors which influence allergic reactions
Emotion and Stress
Colds and viral infections
Certain foods and Medicines
Contrary to the popular view published in many papers and emphasised by the anti-carpet press there is now increasing scientific evidence that disputes that early exposure to environmental allergens (dust mite and cat) causes asthma in childhood A study in Germany recording the medical history and exposure to allergens of approximately 1000 children over 7 years drew the conclusion that the data recorded did not support the hypothesis that exposure to environmental allergens causes asthma in childhood, but that the induction of specific IgE responses and the development of childhood asthma are determined by independent factors. (4)
Since allergic illnesses are a complex subject influenced by the interaction of various factors it is dangerous and scientifically invalid to isolate just one factor as the sole cause of the UK asthma problems.
Other new scientific developments which should be considered
Scientists seeking to explain the increase in childhood asthma have to ask the question “Do people live in a more toxic environment (with greater exposure to more allergen) or are individuals more susceptible to sensitisation for some reason?” In the case of the dust mite humans have cohabited with them since prehistoric times and there are proportionally no more mites now than there ever were. Mites existed in bedding in large numbers in the 60′s and 70′s when asthma incidence was lower and there is no evidence to suggest cat populations are on the increase. There has to be another explanation.
Research has recently highlighted the effect of the modern westernised diet on the propensity for an individual to become sensitised. The reduction in the intake of anti-oxidants, (which suppress inflammation) in the form of fresh fruit and vegetables is linked to the rise in allergic diseases, and has resulted in the population in the affluent modern Western world becoming increasingly susceptible to sensitisation to allergic disease, including asthma (5).
Professor Seaton of Aberdeen University, who has carried out this work, observed the example of Saudi Arabia where the climate is very dry, a condition which prevents dust mite survival. Its move towards a more westernised diet of convenience foods in the cities has led to more than three times the level of asthma compared to rural areas with their traditional diet including fresh fruit and vegetables.
A further report, by Professor K H Carlsen of the Vokentoppen Children’s Asthma and Allergy Centre in Oslo, has suggested that the presence of chlorine in (swimming) pools is a major cause of asthma attack and chronic stress has been also been shown to be a major factor in triggering an asthma attack. (6)
In his report “Industrial Air Pollution and the Country Doctor”, quoting a large number of references, Dr D Van Steenis argues that the increase in asthma is closely associated with high levels of pesticide and fine airborne particulates resulting from industrial processes and combustion products, particularly of waste oil based fuels. He further argues that the U.K’s asthma epidemic is limited to areas of high pollution by fine particulates (PM2.5) and that unpolluted areas have asthma incidence as low as 1%.
A great deal of research has been carried out on the subject of asthma and major differences exist between scientists on the many factors which influence the illness. There is common agreement between the world’s top scientists that carpet is not a major factor, which influences the illness.
THE DUST MITES AND THEIR HABITAT
Dust Mite Habitat.
In order to thrive, dust mites require food (flakes of human skin), moisture (in the presence of some species of mould such as Aspergillus Penicilloides) and a dark warm habitat. Dust Mites need a narrow range of high temperature and humidity conditions to thrive. Dust mites populations show optimal growth at conditions between 18ºC to 25ºC and 60% to 70% relative humidity, conditions of temperature and humidity rarely found in carpet in homes in the UK. Furthermore, when the relative humidity falls below 50% the dust mites desiccate and die (7).
The dust mites feed on the dead scales of skin, which the human body constantly sheds at a rate of 5g per day. The scales are too dry and horny when they flake off the human body for the mites to eat and they need to condition in a moist atmosphere for a few days to absorb water from the air, and to promote the growth of miniature surface moulds, before they are suitable as mite food. Since water is not readily available in carpet the mites depend upon the absorbed moisture for their entire water needs (8). Since the dust mites require such an extreme range of conditions to survive it is common to find carpet completely free of mites or with very low concentrations. Hysterical claims that, as many as 100,000 dust mites ‘may’ be found in a square metre of carpet have no scientific validity.
Bedding on the other hand offers ideal conditions for dust mites to live and thrive which are not dependent upon the ambient relative humidity of the bedroom. We spend approximately one third of our lives in bed during which time the body loses approximately one litre of water each night through perspiration and breathing. During this period the body continues to shed skin scales which are concentrated in a relatively confined area and so the bed provides a dark, warm, humid and food rich environment for the dust mite with long periods of intimate contact between bedding nose and throat.
In a Dutch study it was found that the level of dust mite allergen in dust taken from mattresses was more than 78 times greater than in dust taken from wall to wall carpet in school rooms, almost 3 times greater than dust taken from carpet in living rooms and 1½ times greater than in dust taken from bedroom carpet. (9) This illustrates the importance of beds and bedding as the main environment for dust mite to thrive and produce allergen.
Surveys of households in Germany have shown that whilst almost 30% of all houses were mite free, 50-60% of mattresses, blankets and upholstery fabrics contained mites (10, 11) but only 16% of wall to wall carpets in living rooms and 45% of bedroom carpets contained them. (12). Most researchers agree that the main centre for dust mites to breed is in bedding and following agitation during bed making the airborne dust mites and their allergen then settle on other surfaces including the bedroom floor and soft furnishings. Migration of the dust mites to other areas of the home then slowly takes place through air changes, agitation and vibration. In schools (where there are no beds) the allergen level in dust taken from carpet is very low and Professeur du Blay of the University of Strasbourg has concluded from a study that there is negligible allergen in office carpet because of the absence of beds. In a study, which examined the health of 98 asthmatic children in Holland, it was found that those children who were exposed to wall to wall carpets suffered no poorer health than children exposed to uncarpeted floors. (9)
Dust Mite Allergen
Live dust mites do not themselves cause allergic reactions but their faecal pellets are the cause of sensitisation and can trigger allergic reactions in some people. These faecal pellets are extremely small measuring about 10-15 microns (1 micron is 1/1000th of a millimetre). When these are held trapped in the pile of carpet they do not pose a hazard to sensitised persons. It is only when they are airborne that allergen particles pose a health problem by being available for inhalation. Airborne allergen settles on all surfaces but whilst hard surfaces, including floors, allow the allergens to become easily airborne through the slightest draught or vibration (13) carpet retains the allergen deep in the pile. It has been found, for example, that the velocity of air over a carpet surface is required to be ten times greater than that over a smooth surface if the same number of particles is to be released into the air. (14).
There is no direct link between the number of mites in a carpet and the amount of allergic faeces present. Production of allergen is very slow and it takes a long time for a significant build up to occur. (8) In a residential environment, wall to wall carpet prevents the allergic material from being released into the atmosphere by holding the fine allergen particles in the pile and improves the quality of life of allergic persons. (15) This has been confirmed by research, which showed that measurements of the level of dust mite allergen in the room air above the surface of carpets, even those containing high levels of dust mite allergen, failed to detect the presence of allergen. These measurements were made over an extended period at only 24″ above the carpet surface. This study, quotes other research (Air Quality Sciences, An Indoor Air Quality Study of Alafia Elementary School, (1994-95) Atlanta, Georgia, U.S.A.) which also found no detectable dust mite allergen above carpet. (16)
In a further study which compared the flooring in fourteen Swedish town halls, it was found that whilst more dust could be collected from carpeted floors than uncarpeted floors no greater amount of dust could be found in the indoor air over carpeted floors. (17) This again confirms the inherent property of carpet to hold dust, including allergen, in the pile preventing it from becoming airborne.
Dust mite expert, Dr John Maunder, Director of the Medical Entomology Centre at Cambridge University is certain that carpet cannot be blamed for allergic reactions. “Only in poorly ventilated humid dwellings can large populations of mites build up in carpets. In dry well ventilated places either no mites exist or they are in such low numbers that no significant production of allergen occurs.” (8)
REDUCTION OF DUST MITE POPULATIONS
It is well recognised that the filter like properties of carpets hold dust including allergen, and as previously discussed, it carries out the important function of holding and preventing it from circulating in the air. Most importantly it holds the dust until it is removed, by regular and efficient vacuum cleaning and periodic carpet cleaning, (19) typical of a regime in a well maintained home in the UK.
The real key to controlling dust mite populations is to control the temperature and relative humidity indoors to prevent the warm, humid conditions that dust mites need to live. The easiest way to achieve this is to ensure good ventilation in the home, particularly in bedrooms, which is the critical zone, and also avoid excessive temperatures. (8)
Cleaning of carpets
The accumulation of dust mite allergen in carpet depends upon the balance between its production and its removal. Production of allergen is very slow and it takes a considerable period for a significant allergen build-up to occur. Although allergen is a very stable compound some is removed from carpet by natural biological or chemical breakdown, most remains until removed by cleaning through normal vacuum cleaning.
The very fine allergen particles and minute flakes of skin, which comprise the food source of the mite, are easily removed from carpet by a proper cleaning regime. A carpet cleaned regularly, in a well-ventilated environment, will not contain enough allergen to affect most people. The vacuum cleaner will ideally have a powerful suction and, have efficient filtration to ensure the retention of the allergen within the cleaner and preventing its release into the air. The British Allergy Foundation has an evaluation and accreditation scheme for vacuum cleaners and asthma sufferers are recommended to use a machine approved by them.
The physical action of vacuum cleaning will probably provide sufficient agitation of the carpet surface to allow allergen particles to be stirred up into the atmosphere. The action of opening windows during and, for a period after, vacuum cleaning will ventilate the room and effectively remove the allergen from the air. (8)
One additional benefit of regular vacuum cleaning is the removal of skin flakes from the surface of the carpet before they condition (i.e. absorb moisture) to the point that they become edible for the dust mite. This reduction in available food supply will reduce mite populations.
Studies involving 13 classrooms in the U.S.A. showed that a single dry extraction carpet cleaning operation reduced the average level of dust mite allergen in carpet dust by 51%. (16) A further study involving 57 homes in Georgia and Wisconsin showed that a single dry extraction cleaning operation reduced the average level of cat allergen (Fel d 1) by over 85%. (20)
Occasional wet extraction cleaning of the carpet is also to be recommended (21) to reduce deep seated dusts and steam cleaning has also been found to be particularly efficient at removing a high proportion of allergen and completely killing the dust mite population. (22).
When a household is ventilated and vacuum cleaning of a normal frequency and intensity is carried out, carpet in UK homes:
- Will not hold sufficient food for dust mites to survive,
- Will contain minimal allergen loads on the surface waiting to become airborne.
- Will not provide an indoor environment for dust mites to live.
WHAT CARPET DOES FOR YOUR HOME
Some organisations have recommended that carpets be removed from the home, particularly in the bedroom and replaced by wood floors in order to produce clinical benefits for asthma sufferers. A paper has been published however, which examines the effect of dust mite control measures and which concludes that “Current chemical and physical methods aimed at reducing exposure to allergen from dust mites seem to be ineffective; these methods cannot be recommended as prophylactic treatment for asthma patients who are sensitive to mites.” (23)
Furthermore, it needs to be recognised that carpets have a very important function in creating a comfortable, safe and easy to clean living environment whilst improving air quality. It has been suggested that wood floors constitute a safety hazard since they are smooth and allow slips to occur. Approximately 15,500 injuries requiring hospital treatment occur in the UK each year as a result of falls caused by slipping on wood floors. (24)
Whilst research has shown conclusively that bedding contains a significantly higher level of allergen and dust mites than carpets (9) no one appears to advocate the removal of bedding. Similarly there is a list of factors known to influence asthma, yet there are no recommendations, for example, that smoking is banned, pets not kept and food not cooked in the home. With regard to dwellings it had been shown that the removal of wall to wall carpeting has no clinical benefits for patients who show an allergic reaction to dust mites (25) but a study of 4634 school children in New Jersey, USA, where asthma is a major cause of school absenteeism has shown that carpet in a child’s room is associated with lower rates of medication use and school absenteeism. (26) Even the anti-carpet Healthy Flooring Network admit in their report that no scientific studies have been carried out which solely deal with the effect of carpet removal on asthma patients. (27) Further proof that carpet exerts a beneficial effect is contained in a recent European Community respiratory health study. The study showed that fitted (wall-to-wall) carpets and rugs in bedrooms were related to fewer asthma symptoms and less bronchial responsiveness. The effect was even more pronounced in individuals already sensitised to dust mite allergen. (18)
Furthermore, there is increasing evidence that allergen avoidance is ineffective. The findings of a recent large cohort study of children up to the age 5 reported that there are no linear relationships between early allergen exposure and the induction of childhood respiratory allergy and reductions in domestic allergen exposure alone are unlikely to have a major impact in decreasing the incidence of childhood respiratory allergies; indeed measures that reduce rather than eliminate allergen exposure may even give rise to an increase in the rate of sensitisation. (41). Elimination of allergen exposure is surely impossible if anything approaching a normal lifestyle is to be achieved.
Furthermore, in recognition of the persuasive argument that the filter like properties of carpet entrap allergen in the pile, preventing its release into the atmosphere, the German allergy and asthma association (Deutsches Allergie und Asthmabund e.V.) stated on their website (www.daab.de) that “The main reservoir of mites is in the mattresses of beds. Further habitats are textile upholstered furniture and carpet. In the case of house dust mite sensitisation, it was formerly always recommended to remove the carpet. The current state of research can no longer uphold this as a general recommendation.”
More recently, in their newsletter, DAAB have announced that fitted carpets provide an advantage over smooth floor coverings for allergy patients. Their research has shown that air in rooms with smooth floor coverings holds, on average 62.9 µg/m3 of fine dust concentration which exceeds the established limit value of 50 µg/m3. The air in rooms with fitted carpets, however, contains an average of only 30.4 µg/m3, well below the limit value. (42)
What happens when a Nation stops using carpet?
In the 1970′s in Sweden there were intensive discussions with some claiming that carpet was a serious breeding place for allergens and a source of harmful contaminants. As a result of considerable publicity supported by various interest groups this debate became a national issue.
Not surprisingly the bad press given to carpet started to affect consumers’ confidence in the product and sales began to fall.
In fact, from 1975 to 1990 the carpet share of the floorcoverings market fell from 40% to 2% as hard floor sales grew by 50% and carpet usage fell by 77%.
And what happened to the incidence of asthma in Sweden during this 15-year period? Well, as carpet usage declined dramatically, allergy cases in Sweden increased by 300%. (28)
This massive study carried out on a national scale in a health aware country like Sweden has shown a dramatic increase in asthma cases in the same 15-year period that carpet sales declined!
Other studies in Sweden, incidentally, have shown that there is no difference in the incidence of asthma between carpeted and uncarpeted schools. (29)
A recently published paper (30) reporting on a specific study involving homes which are carpeted and homes with hard floors shows that there is no difference in the level of airborne particulates between homes with and without carpets. The report concludes that airborne particulates, which include allergens, are suppressed by carpet.
Very recently, from a symposium on the topic of the increase in allergic disease the following commentary has emerged. “It has been said that for every problem there is a simple answer that is wrong. Nowhere has this been better demonstrated than in the case of explaining the rise in asthma and allergies. Two superficially attractive ideas (they were never more than speculations), that the answer lay in increased air pollution and/or dust mite populations in houses, attracted the attention of the media and are now widely believed to be the truth. Those who promote such speculations as truth may not always consider the consequences, the major one of which is a potential waste of resources in tackling the wrong problem”. (31)
It should be clearly noted in this context that two of the speakers at the symposium – T Platt-Mills and A Woodcock have, in the past, written academic papers linking carpet, dust mites and asthma but research has moved forward and this link was no longer made at the symposium. However, academic papers by them and others remain in libraries and may be quoted, although no longer valid.
National guidelines for control of infection in health care areas highlight the advantages of carpet in terms of enhancing the environment, noise reduction and reducing the incidence and severity of slips and falls. There is only limited epidemiological evidence that carpets influence health care associated infection rates And there are no guidelines against the use of carpets in health care areas. Avoiding the use of carpet in areas particularly prone to spillages such as laboratories and around sinks etc and also in areas where patients are at particularly high risk from airborne pathogens such as Stem cell transplant units, burns units, intensive care units and operating theatres is considered prudent. (32)
CARPETS AND INDOOR AIR QUALITY
Typically all manufactured materials and products emit gasses from VOC’s (Volatile Organic Compounds) for a period of time. These may have a distinct odour and are, therefore, perceived as dangerous. There are a great number of VOC’s and different materials emit different mixes and concentrations of VOC. The distinctive smell of the interior of a new car, for example, is the result of VOC emissions, and is perceived as desirable to many people. All too soon the distinctive smell diminishes and disappears as the VOC’s are released into the atmosphere.
New carpet smell
The new carpet smell is the result of VOC emissions, usually from the backcoating material and it too will diminish and disappear in time dependent upon the level of ventilation in the room.
According to studies by leading research organisations in the US and Germany, the contribution made by carpet to indoor air pollution is minimal compared with many other indoor finishes and materials. Taking paint as being rated as 100, relative emissions are adhesives 72.5, wall coverings 8.5, plywood 1 and carpet 0.5. (i.e. a carpet emits 1/200th of the VOC gasses given off by paint). Such a low level of emissions from carpet does not constitute a health risk for consumers. (33)
Some adhesives used for the installation of some carpets may contribute to VOC levels and should be used in well ventilated areas which should continue to be ventilated for some days after installation has been completed. Modern adhesives, which have been recently introduced, have significantly lower emission levels.
Indoor Air Quality
Many people are concerned about indoor air quality. An analysis of the air in a new office building in the USA where the workers were complaining of discomfort and illness found that the enclosed heated and air conditioned environment recirculated rather than dispersed emissions from the indoor wall, ceiling, floor, and furnishings. Ventilation, introducing fresh air removed any problems.
Many key research papers show that carpet, in fact, contributes significantly to cleaner indoor air. Three major pollutants of indoor air quality are formaldehyde which is emitted from a wide range of building products, oxides of nitrogen and oxides of sulphur both of which are by-products of combustion processes (e.g., gas cookers and heaters).
Research has shown that wool is particularly effective absorbent of these gases (34, 35). A study in the US has shown that wool has one of the highest rates of removal of nitrogen dioxide from the atmosphere (36). Because of the 3 dimensional nature of carpet with the wool fibres in the pile standing vertically from the backing, the wool fibres present a considerable fibre area for the absorption of gases. One square metre of carpet containing 1Kg of wool will present a fibre surface for gaseous absorption of 100 square metres. (37)
Other studies have shown that large amounts of sulphur dioxide are also absorbed and held by wool fibres in carpet. (38)
Carpet, therefore, contributes significantly fewer emissions than do other building materials, indoor furnishings and finishes. The capacity for carpet to absorb airborne pollutants and to hold these makes it a significant contributor to good indoor air quality.
CHEMICALS IN CARPETS
Carpet manufacturers in the UK recognise their responsibility towards the environment and do not generally add dangerous materials to their products during manufacture. The requirements of the OSPAR convention are recognised and understood and those chemicals listed under this agreement which might find their way into carpet are being phased out within the required time scale. (The OSPAR convention is the main inter-governmental agreement to regulate and control marine pollution in the North Sea and the North Atlantic.)
Generally speaking if minute traces of toxic chemicals are found in carpet they will almost certainly be there as a constituent of one of the raw materials used in carpet manufacture, particularly those which may be sourced outside the modern western world.
The results of a Healthy Flooring Network study would have you believe that carpet manufacturers inevitably include a range of dangerous chemicals in their products but it must be clearly understood that the small sample of carpet tested in their 2000 study was not in the least representative of the wider range of products made by British carpet producers and some products analysed in the study were carefully selected since the chemicals found were indeed likely to be present in the products since they were advertised accordingly There was, furthermore, no information relating to acceptable human exposure levels of such chemicals or comparisons with background levels of these chemicals in the everyday environment.
Two carpets tested, were found to contain small traces of Organo-tin compounds as “anti-dust-mite” treatments. The treatment applied has since been re-formulated and contains no organo-tin compounds. Those carpets containing a high proportion of wool in the pile were found, not surprisingly, to contain Permethrin. A chemical treatment used to impart insect (moth) resistance. There is no evidence to suggest that the very low levels found in these carpet samples have any adverse effect upon human health.
Brominated Fire Retardants were found in 3 products, two of which were not produced in the UK and were constructed with polypropylene fibre, a product with less inherent fire retardancy properties than other popular carpet fibres.
Formaldehyde was found in small amounts in a number of samples, which is also not surprising when wool is known to absorb formaldehyde from the atmosphere (contributing to cleaner air).
It is possible that some of these chemicals may have been included in raw materials down the supply chain and therefore present in the carpet without the knowledge of the carpet manufacturer.
Organo-tins and Brominated fire retardant are two of the chemicals in the OSPAR list of 32 chemicals which are to be phased out, by agreement, by 2020 at the latest.
The study concludes that these potentially toxic chemicals were found in some (but not all) samples and goes on to say “although the consequences of long term exposure to chemicals such as these, in the indoor environment is uncertain, the above chemicals have properties which make them potentially hazardous to human health and the environment”(39). The words potentially and uncertain should be noted!
An article published in New Scientist magazine (5th May 2001) alleged that living indoors exposes us to much higher levels of toxins than being outdoors. This article is based on US experience and is not directly comparable to experience in Britain.
As pointed out above carpet is acknowledged as a reservoir for dust, which sinks to the base of the pile. The dust may well contain minute traces of toxins and absorb others but, clearly, these toxins did not originate in the carpet and in any event they would have also contaminated other indoor surfaces. Research has shown that only 1% of dust in carpet is available on the carpet surface, (40) the remainder being held in the pile until such time as it is removed by normal cleaning.
* This article is taken from The Carpet Foundation’s website
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