Breathe easy in your home
When you think about air pollution, car fumes, smog and fumes from factories probably spring to mind. But the reality is, the air inside your home could be more polluted than the air outside. We spend between 75 to 90 percent of our time indoors, more for infants and the elderly.
In many New Zealand homes – particularly newer ones – building materials, paint, glues, carpets and other finishes and furnishings emit chemicals that can be harmful to your health. These chemicals can trigger asthma and a range of other ailments.
Houses that are damp provide the perfect conditions for mould and dust mites to grow. These also have associated health risks.
You can protect yourself and other members of your household by carefully choosing the materials used in your home, keeping your home warm, dry and well-ventilated, and by making some simple lifestyle choices – such as keeping your carpet clean.
Why do pollutants matter?
The health impacts vary according to the type of pollutant but can include asthma, headaches, fatigue, coughing, sneezing, dizziness, and irritation of the eyes, nose, throat and skin.
The effects of pollutants can be acute and immediate (for example, allergies from dust mites) or chronic over a long term (for example, formaldehyde and spores from fungi).
Exposure can occur soon after occupying a new home and may be ongoing during the life of the house if the sources are not addressed.
While pollutant levels from individual sources may not pose a significant health risk by themselves, many homes have multiple sources of indoor air pollution that can interact together.
Types of pollutants
Volatile organic compounds
Volatile organic compounds (VOCs) are chemical substances that become airborne at room temperature and can be inhaled. They are emitted by a range of materials and household products including paints, cleaning products and many furnishings.
A common and toxic VOC is formaldehyde, which is released from some plywood, fibreboard (MDF), furniture and glues.
Some studies have found a link between home exposure to VOCs and incidence of asthma (see the European Respitory Review and Lawrence Berkeley National Laboratory websites).
In general, you'll be exposed to more VOCs from building materials, furniture and finishes when:
the materials are new
conditions are hot and humid
the house is isn’t adequately ventilated with fresh air.
Some materials emit pollutants continuously, although the quantity can decrease over time.
Mould and dust mites
According to a 2015 BRANZ survey, almost half of New Zealand’s homes have mould. Mould, with its tiny spores, is at the root of many respiratory illnesses and asthma as well as some forms of gastroenteritis. Dust mites also thrive in humid environments, which can exacerbate allergies in some people.
2015 BRANZ House Condition Survey [PDF 750KB]
Other common pollutants
Other common pollutants include:
airborne particles from fireplaces, wood stoves and tobacco smoke
noxious gases such as carbon monoxide and nitrogen dioxide from unflued gas heaters, leaking chimneys, wood and gas stoves, car exhaust gases in attached garages and tobacco smoke
airborne sprays from air fresheners, cleaners and pesticides used indoors, and from products used on lawns and gardens that drift or are tracked inside the house
other biological contaminants include bacteria, animal fur and pest droppings – these create fine breathable particles that contribute to allergies and respiratory disease
chemicals used on carpets to repel insects and stains.
Renovating
Renovation can release toxic substances (such as lead-based paint dust), so check materials at the start and take the necessary advice and precautions.
Older homes can have asbestos, in the form of:
cement panel products
pipes and flues
glues and sealants
roof cladding
insulating board and lagging on pipes
decorative texture coatings on ceilings and walls
lino or tile backing.
https://www.smarterhomes.org.nz/smart-guides/air-quality-moisture-and-ventilation/managing-pollution-and-unhealthy-air/
http://blog.ecostore.co.nz/site/article/how-to-reduce-exposure-to-vocs-in-your-home
Volatile organic compounds (VOCs)
Volatile organic compounds (VOCs) include a wide range of hydrocarbon compounds that are emitted as gases from different materials. Many building materials that are used and produced in the manufacture of paints, resins, adhesives, polyurethanes, epoxies, solvents, sealants and some cleaning products contain VOCs. The term ‘organic’ indicates that the compounds contain carbon.
They can have a range of effects on occupants including headaches, dizziness and respiratory irritation. Long-term exposure at high levels, which is more common at the workplace than at home, can cause kidney and liver effects, cancer and chromosomal damage.
VOCs can be controlled by careful choice of products and by ventilating the house well. It is important to know that VOC levels are quite high when a house is just built while materials off-gas their most freely evaporated volatiles but VOC levels then fall as time goes by.
Building products that release VOCs include:
paints, polyurethanes and varnishes that are manufactured from formaldehyde, mercury, arsenic, selenium, lead or cadmium
adhesives and resins
solvents
wallpaper, vinyl and carpet
furnishing foams and fabrics
LOSP-treated timber
manufactured wood products such as some particleboards, medium density fibreboard (MDF) and plywood.
Cleaning products and chemical processes
VOCs may react together and produce other compounds. Over 900 compounds have been identified in buildings including toluene, xylene, styrene, acetaldehyde, paradichlorobenzene, ethylbenzene, chloropyrifos, tetradecane, di-n-butyl phthalate and diazinon.
Formaldehyde and urea-formaldehyde
Formaldehyde is a chemical used extensively in the manufacture of building materials and household products. It is also a byproduct of combustion from unvented, fuel-burning appliances, such as gas stoves, unflued gas and kerosene heaters and from cigarettes.
It is commonly used in the production of resins and glues (urea-formaldehyde products), which are incorporated into many building materials, particularly manufactured wood products such as some particleboards, plywood and medium density fibreboard (MDF).
Formaldehyde and urea-formaldehyde gases have an irritating, pungent odour and are considered to have an adverse effect on health and performance when levels are above about 0.1 parts per million (ppm).
They will off-gas at room temperature particularly when the building products are new, so new buildings should be well ventilated, particularly during construction and for the first 4–6 weeks of occupation, to allow new building products to off-gas most of their formaldehyde and thus reduce the risk of formaldehyde gas irritation.
Controlling VOCs
VOCs are primarily released when materials or products are newly installed or applied. Over time, the level of emissions will reduce.
VOC emissions can be controlled by:
providing adequate ventilation, particularly during construction and the first 4–6 weeks of occupation
using low-VOC or VOC-free building materials/products
sealing materials, where practicable, to contain the VOCs by using low-VOC or VOC-free polyurethane, or alkyd or acrylic paints.
http://www.level.org.nz/passive-design/controlling-indoor-air-quality/controlling-airborne-contaminants/
https://www.sgs.co.nz/en/transportation/automotive/mechanical-components/raw-materials/plastics/voc-testing
Types of Stains and Finishes
Wood stains, which can be oil- or water-based, contain dyes or pigments that soak into the wood to accent the grain. Clear wood finishes—varnishes, shellacs, lacquers, natural oils and water-based finishes—protect wood from moisture or sunlight.
Water-Based Stains
Water-based stains typically emit fewer VOCs, can be cleaned up with soap and water, and dry quickly. However, avoid stains that contain glycol ether solvents, which can be toxic, by asking the manufacturer or checking the MSDS. A clear water-based finish can be used on top of a water-based stain to increase durability.
Natural Oil-Based Stains
Natural (plant-based) oil-based stains are durable and, unlike water-based stains, do not require a sealer. But they may have higher VOC emissions. Oil-based stains with lower VOCs may be a good choice for some projects.
Oil or Synthetic-Based Stains
Oil or synthetic-based stains with acrylic or urethane binders can contain harmful chemicals and release high levels of VOCs. These stains are more water-resistant than water-based stains and are most often used outdoors.
Natural Oil Finishes
Natural oil finishes, like linseed or tung oil, are plant-based and less processed than other finishes. Natural oils provide protection by penetrating the wood, although they are less protective than varnish or lacquer. They often have a lower VOC content compared to varnish, but they may require many coats, take up to a week to dry, and they typically must be reapplied yearly. Note that toxic drying agents such as lead, arsenic, beryllium, chromium, cadmium or nickel may be added to reduce curing time; cobalt and zirconium may also be added, but they are less toxic.
Tung oil cures in a few days and does not usually have added drying agents, but since it comes from nuts, some people may be allergic.
Water-Based Finishes
Water-based stains typically emit fewer VOCs, can be cleaned up with soap and water, and dry quickly. However, avoid stains that contain glycol ether solvents, which can be toxic, by asking the manufacturer or checking the MSDS. A clear water-based finish can be used on top of a water-based stain to increase durability.
Varnish
Varnish—acrylic or urethane—provides the best heat, water and chemical resistance compared to other finishes for indoor projects. However, they contain petroleum and synthetic ingredients that emit high levels of VOCs. They create a long-lasting finish, especially for floors, but require harsh solvents for cleanup. We don’t recommend them for most indoor projects.
Lacquer
WaterAcrylic-based lacquer does not form as hard of a coating as most types of varnish or water-based sealers, often is high in VOCs, and likely contains toluene and xylene solvents.
Shellac
Shellac is a natural resin made from an insect. It has fewer environmental impacts compared to lacquer and varnish, and is a renewable resource. Shellac usually employs ethanol as the solvent, but can be made with methanol, which should be avoided. Shellac dries quickly, but its durability is only fair, so it should be coated with a water-based sealer if used on wood floors in high-traffic areas.
https://www.ewg.org/healthyhomeguide/wood-stains-and-finishes/#.W7MNIS2B06g
Stains and Finishes
There are many coating choices for wood surfaces in addition to paint. These products protect wood from physical damage, water, UV damage and rot; they also enhance wood’s beauty by adding sheen and, sometimes, color. Most of these products need to be applied more regularly than paint and significantly increase the carbon footprint of wood, which, when left to weather naturally, is a material with extremely low embodied energy.
There are two general categories of wood finishing products. Film finishes form a protective hard coating above the grain; penetrating, oil-based finishes soak into the wood. Like paints, wood-finishing products contain resins and a solvent. Traditionally, plant- or insect-based oils were used as resins and thinned with turpentine. Today, resins or binders are often petroleum-based compounds, including acrylics, vinyls, alkyds, cellulosics, epoxies and polyurethanes. Alkyd- and polyurethane-based varnishes are high in VOCs; acrylics are lower. There has also been a resurgence in products that use natural resins as the base.
Solvents and/or thinners used in wood finishing products include alcohols, ketones, glycol ethers, petroleum distillates, turpentine and water. As with paints, a number of manufacturers now offer lower-VOC, water-based alternatives.
In general, stains are lower in VOCs and last longer than clear finishes. (According to the Western Red Cedar Lumber Association, solid stains on textured wood need to be reapplied every four to six years; semi-transparent stains every two to four years.) Benjamin Moore offers its ARBORCOAT line of low-VOC waterborne stains and finishes in five opacities. They use the same patented colorant technology as the company’s low-VOC paints, so the total VOC concentration with colorants will not exceed 100 g/L. Penofin Verde is a no-VOC wood stain that is appropriate for both interior and exterior use. As is the case with all Penofin wood-finishing products, its base is Brazilian rosewood oil, which is sustainably harvested from the tree’s pods. It boasts less than 1 gram VOCs/L and 99 percent UV protection.
Sansin offers an entire line of Enviro Stains and finishes that are made from tree oils. Modified natural oils and resins are carried deep into the wood’s cell structure, using water as a carrier. As the water evaporates, Sansin bonds directly with the wood substrate, forming a tough, durable barrier that won’t crack, peel or blister. Sansin even offers a recycled product. Eco2 Exterior is a durable, two-coat finish designed for vertical wood surfaces; it is made from recycled Sansin products and is available in four colors.
AFM Safecoat does not use formaldehyde in its manufacturing processes or products, and the company offers an entire line of LEED-qualified stains and finishes. Its DuroStain semi-transparent stain is appropriate for all wood surfaces and contains no aniline dyes, gilsonite, aromatic solvents or formaldehyde. Its very low VOC content also meets all federal and state air quality regulations.
https://www.greenbuildermedia.com/iaq/low-voc-paints-stains-finishes