More than any other room in the home, the kitchen has changed beyond recognition in the last half century. Where once there was a cramped space designed for one purpose, now there is an open multi-functional space. Where once a housewife hid herself away to cook, now the entire family cooks, eats, watches tv and carries out school work. And now, catalysed by stay at home orders, it must often double up as a home office.
This change means the kitchen is an area of high traffic with many different sources of asthma and allergy triggers. Cooking and cleaning introduce particles and allergens into the air; flooring, paints and insulation can release potentially harmful chemicals; insects, attracted to food, can act as triggers; pollen is brought in on clothing from outside. Furniture, sealants, glues and home office equipment can emit harmful chemicals and furthermore, the kitchen is where a pet is most likely to spend its time.
In the context of building/designing a room for those impacted by asthma and allergies, the kitchen has the potential to become a complex project. Previous articles have covered the concepts of environmental control, allergen and chemical exposure, the issues of paint and humidity and these are all applicable to the kitchen project too. For this article, I will focus on the relevance of flooring, insulation, cleaning products and air cleaners and how design thinking can help solve complex issues.
1. Kitchen Flooring
Flooring covers a substantial proportion of the kitchen and so any emissions from installed flooring can contribute significantly to the indoor air quality. Choice of flooring may seem overwhelming as there is a wide variety available. Among the considerations are the chemicals that may be emitted from the material.
Harmful Chemicals in Flooring May Include:
Phthalates. Phthalates are plasticisers that are used to make rigid plastic more pliable and flexible. Phthalates are potential carcinogens and are linked to asthma, birth defects, learning disabilities, reproductive problems and liver toxicity. They have been banned from children’s toys for almost 15 years, but not from other common household products.
Volatile Organic Compounds(VOCs). VOCs are chemicals emitted as gases from liquid and solid materials. VOCs are a known asthma trigger. They can also cause eye, nose and throat irritation, headaches, loss of coordination and nausea, damage to liver, kidney and to the central nervous system.
Formaldehyde. Formaldehyde is a volatile organic compound. In larger quantities, formaldehyde can cause respiratory problems and skin irritation. It may cause exacerbation of asthma and cause allergic contact dermatitis, irritation of the eyes, nose and the upper respiratory tract.
Biocides and Fungicides. Biocides and fungicides may be added to flooring to prevent the growth of bacteria and fungi. These may include silver, ammonium bromide and mercaptobenzothiazole. Biocidal chemicals used in flooring can be sensitizing and can also cause contact dermatitis and respiratory irritation.
Organo-tin compounds. Because PVC may degrade or discolour at higher temperatures organo-tin compounds may be used as heat stabilisers. Organo-tins however have been shown to be toxic to immune system and to the reproductive system.
All of these chemicals can pose a potential risk in the kitchen and the choice of flooring type can have a major impact depending on an individual’s sensitivity to certain compound and material.
A second consideration is the adhesive used when installing the floor. Adhesives used to secure the flooring can produce harmful chemicals that can impact on those with sensitive airways. Click fit or nail-down installation should be considered instead of adhesive. If an adhesive must be used, select a low-VOC type. Third party certification is a good guide when choosing low emission flooring and adhesive.
Finally consideration must be given to the interaction of the flooring with potential allergens and how the flooring should be cleaned. Sticky allergen particles can be more difficult to remove from some types of flooring and if a floor necessitates the frequent use of strong chemical-laden cleaning products which themselves can release harmful chemicals, then it may be a poor choice in the long run.
Linoleum or laminate wood flooring are easy to clean and so have been recommended for a long time for those suffering from asthma and allergies. However, laminate or linoleum type flooring do not retain dust and allergens- unlike carpet which may trap/retain dust and allergens- and regular mopping and cleaning is required to prevent aerosolization of dust and particles as people walk on the flooring. Easy to clean surfaces, so that irritants and allergens can be kept to a minimum without too much effort, is crucial.
Natural material such as solid wood floors, tiles or recycled wood can also all make good choices that are less chemically treated. However, natural flooring materials can be very expensive. This must be balanced against the fact that cheaper products are more likely to be manufactured with potentially harmful chemical ingredients.
The choice of flooring can be difficult but should be driven by knowledge of the sensitivities of the occupant. It is essential to consider which type is most appropriate for the individual client and has less impact on asthma and allergies.
A new build provides a unique opportunity to ensure the kitchen as healthy as possible from the inside out. But if the project is a renovation or redesign of an existing room, it may be tempting to leave the current insulation in place. Before making that decision it is worth considering that as insulation deteriorates, it can become a threat to indoor air quality.
Over time, old insulation may introduce more and more dust particles and volatile organic compounds into the air. Insulation may also be providing a home for pests such as rodents and cockroaches. A cockroach allergy is a common trigger of year-round allergy and asthma. Studies show children who are allergic to cockroaches, and are exposed to them, need to go to the hospital for asthma more often than other children with asthma.
Insulation that has become wet is not only rendered useless but may also become moldy. Mold can cause sneezing, wheeze, cough and itchy skin even in those with no respiratory issues. In those impacted by asthma, it can be a serious trigger.
Choosing new insulation is a decision that must be made carefully because although insulation has many benefits- reduced energy costs, thermal comfort, mold reduction- it may contain chemicals that trigger asthma and allergies.
Considerations when choosing insulation include:
- Spray polyurethane foam has been shown to induce asthma.
- Formaldehyde, required for chemical foaming action in urea formaldehyde foam, is a VOC that can irritate the airways and the skin. It may cause exacerbation of asthma and cause allergic contact dermatitis.
- Due to the flammability of polystyrene, insulation made from this material must contain fire retardants. These fire retardants, such as HBCDD, can cause risk to health through inhalation, and are listed by the European Union as a ‘substance of very high concern’.
- Isocyanate, which is needed for the foaming action in polyurethane foam and urea formaldehyde foam, may cause contact dermatitis, lung damage and asthma.
- Mold, mildew and dust can collect in insulation, which can reduce indoor air quality. It can also release dust and fibers into the air when it is being installed. Airborne fibers and dust can irritate the eyes, nose, throat and lungs. This can affect anyone, although the effects are likely to be more serious in those with asthma or allergies.
- Fiberglass insulation is a material which can be made without some of the potentially sensitising chemicals that are present in some types of insulation, such as halogenated flame retardants. It is a reasonable, cost-effective option for consumers wishing to find healthier options for their homes.
- Familiarity with your client’s asthma or allergy triggers will help guide you in selecting an appropriate insulation product.
3. Cleaning Products in the Kitchen
An effective home allergen reduction program includes the regular removal of allergens and irritants from fabrics and hard surfaces. However, sometimes the cleaning products used for this purpose can have harmful chemicals that can actually trigger asthma and allergies. How a material, fabric or surface should be cleaned therefore has implications for the builder/designer/architect. For example, the advantage gained by choosing a low-emitting flooring product may well be rendered useless if the floor requires very regular cleaning with high strength cleaning products to keep allergen levels low. It is also worth considering that due to the nature of the space, the kitchen is where cleaning products are most often used.
There have been many studies linking asthma in adolescents and adults with cleaning products. In fact, one such study found that regular use of cleaning sprays has an impact on lung health that could be as bad as smoking a pack of cigarettes a day.
A recent study published in the Canadian Medical Association Journal has shown an association between use of household cleaning products in the first few months of a child’s life and risk of childhood wheeze and asthma at age 3. The study showed that some products are more dangerous than others, namely the more scented the product the more harmful.
Household cleaning product ingredients are many and varied. They are also largely unregulated in the United States. Manufacturers are not obliged to list all the ingredients on the packaging; anything that constitutes less than 2% of the product can be omitted. The American Lung Association recommends using only cleaning products that “don’t have volatile organic compounds, fragrances, irritants or flammable ingredients” and that air fresheners should be avoided altogether.
Terms such as ‘hypoallergenic’, ‘natural’ or ‘pure’ should not be taken to mean free of allergen or harmful chemicals. These terms are not based on scientific testing and should be considered as marketing terms only. This was made particularly clear when Palmolive ‘Pure and Clear’ soap used the term hypoallergenic, despite the fact that the soap contained a chemical so harsh that it was named by the American Contact Dermatitis Society as the allergen of the year in 2013. Similarly, in the context of allergen avoidance, the terms ‘eco’ and ‘organic’ should be approached with caution. These terms indicate that the product is good for the earth, not necessarily for the human and have generally not undergone testing from the perspective of asthma and allergy triggers.
The relevance of cleaning products in the design of a renovation or building of a kitchen for those impacted by asthma and allergies is clear. When choosing a product, it is simply not sufficient to consider a product in isolation. It is essential, if you are to be successful in your build, to be aware of the performance of the product in situ, over time, and how it reacts and interacts with other materials and with the occupants of the room.
Factors to consider when choosing cleaning products:
- Never mix different products as doing so risks a chemical reaction which could release hazardous by-products into the air
- Spray product into a cloth first
- Rinse off the cleaned areas afterwards
- Open a window to ventilate during and after cleaning to ensure a supply of fresh air
- If you have an air filter, turn it on while cleaning and for a period after
- Wear gloves/other PPE as directed by manufacturer’s instructions
- Generally, products with fewer ingredients are safer
- Check the veracity of any seals/certification marks on the product
4. Air Cleaners
The kitchen, as a multifunctional space, can have multiple sources of pollutants that are detrimental to the indoor air quality and potential triggers of asthma and allergies. Cooking is a major source of pollutants, both from the appliance used to cook and from the cooking of the food itself. Applying heat to food produces all types of particulate matter (particulate matter, or PM, refers to small solid or liquid particles floating in the air, made up of different substances like carbon, sulphur, nitrogen and metal compounds.) Fine particles (PM2.5) and ultrafine particles (PM0.1) are particularly harmful to health as they can penetrate deep into the lungs and enter the bloodstream. One study has found that cooking a Sunday roast or Thanksgiving dinner could produce higher levels of PM 2.5 than are found on the streets of Delhi – one of the most polluted cities in the world.
About a third of US households cook primarily with gas – which emits nitrogen oxides and carbon monoxide, in addition to the particle pollution that all types of stoves produce. Even small increases in short-term exposure to nitrogen dioxide can increase asthma risks for children. One study found that children in homes with gas stoves have a 42% higher chance of having asthma symptoms. More recent research from the EPA has also linked long-term NO2 exposure to cardiovascular effects, diabetes, poorer birth outcomes, premature mortality, and cancer.
While both gas and electric ovens can produce pollutants such as particulate matter and formaldehyde during regular use, self-cleaning ovens have the potential to emit the highest levels of airborne pollutants. As food debris is burned away, potentially harmful concentrations of particulate matter, nitrogen dioxide, carbon monoxide and formaldehyde are released into the kitchen air. While the oven and stove are probably the most significant sources of airborne pollutants during cooking, even toasters, deep fryers and woks can release particulate matter and VOCs into the air.
But cooking isn’t the only source of pollutants in the kitchen. Cleaning products, furniture, paints, sealants, air fresheners, building materials and pollen are all potential contributors to poor indoor air quality. Pet dander too is a common trigger found in the kitchen as this is the room a pet is most likely to spend its time. If the kitchen doubles up as a home office, then computers, printers and ink emit VOCs that will be added to the mix.
Increased ventilation will help to improve indoor air quality and a properly installed stove hood or fan, vented outdoors is a must for the kitchen, but simply due to the nature of the modern multifunctional kitchen this may not be sufficient and an air cleaner should be considered. Effective air cleaning devices can be a very useful part of a multi-faceted approach to allergen reduction.
Air cleaners may have one or more modes of filtration. A HEPA filter is a good choice for those impacted by asthma and allergies as it can trap 99.97% of particles 0.03microns or smaller, which includes pollen spores, pet dander, dust mites, PM2.5 and some bacteria. On the down side, a HEPA filter will not remove odours, chemicals or gases. For that you will need an activated carbon filter – it is effective at removing bad odours, VOCs and smoke. Often, an activated carbon filter will be combined with a HEPA filter for more effective filtration.
A UV sterilizer uses the same UVA and UVB rays emitted by the sun to kill mold, bacteria and even some viruses. And an ioniser or electrostatic filter works by combining negatively charged oxygen atoms with positively charged ones such as dust and pollen. Importantly, an ioniser doesn’t eliminate or absorb contaminants and so there is the potential problem of the particles becoming loose and re-entering the air.
Choosing an effective air cleaner means considering the following factors:
- It is important that the air cleaner can remove allergens from the air, and that these are captured in the filter of the air cleaner, not just redistributed around the room.
- Different allergens act differently in the air because they have different sizes and features, so the air cleaner must be capable of removing particles of different sizes.
- Emission of ozone from the air cleaner must be within the Code of Federal Regulations Guidelines.
5. Design thinking and empathic listening
Applying a design thinking approach to the building, renovation or design of a kitchen can help achieve an ideal result for a client impacted by asthma and allergies. Through empathic listening, and the cultivation of an open relationship with your client the unique issues that concern the client can be unearthed. What may seem a complex, complicated project can be simplified and once the individual circumstances that are at the core of that client’s needs and wishes are understood, the right solutions can be sought and realised.
The application of design thinking to the construction industry has caused a necessary shift in the industry from an engineering focus to a people-centred, healthy, design approach. It forces us ask the question, what is the impact the product/building on the consumer’s environment and the effect this environment has on health. It is not enough to deliver a ‘cut and paste’ build/renovation anymore. Our knowledge of building materials and the impact indoor air quality can have on human health means that we have a responsibility to the client to deliver a home that will impact positively on their health and wellbeing.
In the modern house, the kitchen is the centre of the home. It is where families gather, eat, celebrate and work but it is precisely this multifunctional aspect of the room that means it has the potential to be a significant trigger area for those with asthma and allergies.
Third party certification of building materials and home appliances act as reliable guides to products suitable for those impacted by asthma and allergies, simplifying the sometimes complex job of choosing the right materials for the client. The asthma & allergy friendly® Certification Mark is one of the few scientifically proven marks that is solely focused on the impact a product has on a consumer’s environment and the effect this environment has on health so it acts as a trusted signpost when planning for those impacted by asthma and allergies. By building a kitchen that is focused on health and wellbeing, you are building a space that acts as a safe, focal point of the client’s life.