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Volatile Organic Compounds
in Housing
Disclaimer:
The information contained in this article represents
my opinion after experience and investigation. I am
not an expert in this field. I advise readers to
consult other sources, their advisers and experts, and
to form their own opinions prior to acting on the
construction or purchase of a house, to ensure that
the house will meet all of their requirements.
I recently (May 2009) visited a set of display homes in a new housing estate. First thing I noticed as I walked into the houses was the odour inside the house. The air was positively toxic with volatile organic compounds (VOCs) (or other odour producing compounds). I could not imagine having to live in these houses for the first few months (or few years!) until these VOCs have dispersed to a large extent. I often worry about the occupants of these new houses, often young families with children. It can't be good for the health of the occupants to live and sleep in such a potentially toxic environment.
"VOCs are chemicals containing carbon that evaporate into the atmosphere at room temperature. VOCs slowly make their way to the surface and ‘offgas’ into the surrounding air. The CSIRO identified 27 airborne toxins in homes more than a year after they were constructed. These included the carcinogens benzene, formaldehyde and styrene, and a cocktail of methanol, ethanol, acetone, toluene, dichlorobenzene plus a number of less well-known toxics, most of which are found in paints. Exposure to VOCs can worsen asthma symptoms; and cause nose, skin, and eye irritation; headaches, nausea, convulsions, and dizziness; respiratory problems; nerve damage and, in some cases, cancer, liver and kidney disease." (Sanctuary Article - link below).
In houses the VOCs would mainly be from the carpets and underlays, painted walls and other surface finishes and from the manufactured timber products (particle board (MDF or chipboard) and plywood, usually containing formaldehyde glues) and other plastics and glues in the houses. (Other sources of VOCs or other harmful substances may also be present - see below.)
For many of the products there are low VOC alternatives. Which sort of begs the question - if it is well known that VOCs can cause health problems in some people and alternatives are available why aren't the alternatives routinely used. I suggest it is probably a cost factor - alternatives can be more expensive (varying from a zero to a lot) and perhaps the labour for handling and construction might be a bit more as it may be slower to work with, - and also lack of knowledge - "if we done it like that in the past it alright for the job now."
One of the situations that cause this to be even a larger problem now is that in order to increase the energy efficiency of a house we are advised to seal the house much better than before. If we do this then there are less air changes per hour or per day than an unsealed house and consequently the concentrations of the VOCs and other odour producing contaminants will be higher. There are a number of ways to address this. 1. Don't seal the house - but then we have to suffer the consequences of greater energy use to maintain internal comfort levels. With climate change requiring us to cut down on the use of fossil fuels for heating this may not be the best solution. 2. Put in a mechanical ventilation system with either a heat exchange system or a solar pre heat arrangement - but then there are the costs of and energy usage in running the heat exchange systems, however quite low for solar preheat (but that only runs when the sun is shining so will not meet requirement for continuous ventilation). 3. reduce the amount of VOCs in the materials used in the construction of the house to limit the off-gassing potential. Of these I think that 3 is an absolute must and 2 solar pre heat ventilation is a good idea.
For paints many of the major paint companies have a low or no VOC line of acrylic paint - although care needs to be taken if purchasing and then tinting the paints at normal hardware stores as the tints are typically loaded with VOCs. Some other smaller specialist companies have genuine low or no VOC (including tints) and also "natural" paint lines.
Carpets are a particular problem with VOCs from the glues used in the backing material on some carpets and artificial fibres, if used. Artificial underlays are also a source of odour. I once put down some new carpet in a room. The odour was so bad I ended up ripping it out again - an expensive lesson. Natural fibre carpets and underlays may be a better alternative - so long as no glues (or glues with VOCs) are used. The other alternative is not to have carpets at all (or only have carefully selected rugs). The alternatives are tiles or plain concrete. Timber floors (or bamboo floors) could be considered but care would need to be taken selecting the polish applied to the floor (low/no VOC or odour - beware that even "natural" alternatives may not meet this requirement).
Timber particle board is used extensively in house construction - for flooring and also built in cupboards and kitchens. The standard particle board contains formaldehyde glues. MDF, a version of particle board, is used extensively for kitchen cupboards. In this usage it is covered with a laminate layer, which the industry usually claims seals in the VOCs, which perhaps it does - I don't know - however the thought of having a potentially dangerous substance sealed in items in the kitchen concerns me. Why do it if there is an alternative? There is a also a low VOC version of MDF - although I once suggested the use of this alternative to a major kitchen cupboard supplier. They of course fobbed me off. The alternative is of course natural timber - the problem is what do you coat / finish the timber with which has low VOC off-gassing. And it is also more expensive.
Other construction glues, after having dealt with the other VOC problems, may be a lesser problem. There are low VOC alternatives if you carefully check at your hardware store. You may have problem getting your builder to use them - they like to use what they know works so may not like changing to a new product. The other alternative is not to use glue at all, just use nails and screws. Again you may have a problem with your builder if you require this.
A word of caution - just because a product claims to be, or is, "natural" does not mean that it is necessarily low odour or low VOC, although it may be claimed that these "natural VOCs" are safer than the VOCs in 'synthetic" products (refer Sanctuary article). Don't necessarily believe the sales pitch of the supplier - read the can or the material data sheet or ring the manufacturer. I was once caught out in this way for a natural oil floor treatment which stunk for months. It may or may not have been dangerous but it was unpleasant to me. Also be careful of what "Low VOC" or "Low Odour" actually means - is there a standard or is it all relative? One person's opinion of what "Low" means might be different to another person's. It is always better to go for "No" if possible.
If a product is low VOC does that necessarily mean that it is low odour. Not everything that produces an odour is classed as a VOC (for example ammonia - chemical composition NH3 - is very odorous but is not a VOC - no carbon) so it is also necessary to check that, as well as being low/no VOC, it is low/no odour - and anyway an odorous substance such as ammonia would be bad for the health if exposed for a long time or high concentrations regardless of not being a VOC. Also no odour does not necessarily mean no VOC - it might be odourless or at a level that can't be detected by the nose. However this said odour is a good indicator that VOCs or other harmful substances may be present.
The level of VOC and / or odour is such in standard project homes that I could not live in one unadjusted. I imagine that the same applies to the majority of standard new house building. To avoid this problem would require a careful specification and then supervision to ensure that the specified products is supplied and installed in the specified manner. In fact if I was to order a house from a project home builder (unlikely, mainly due to the poor energy efficiency of their product) or through a normal builder I would be tempted to just get it built to lock up and then do all the internal fit out and finishing myself, or arrange it separately so I could investigate and order the materials myself and have direct control of installation or application (DIY or subcontract). (For example for the kitchen cabinets I will order them to be constructed from pine and delivered unstained or polished. I will then install and polish them in situ. Bench tops will be stainless steel, wood, cement or porcelain, though cement and porcelain tiles products can sometimes require the use of chemical sealants which may contain VOCs.) It is often in the fit out and finishing that the majority of the VOCs are introduced into the house fabric.
(The second major source of VOCs in the houses are furniture etc introduced into the house by the owner. Consequently often it is a double banger in a new house - new house and new furniture. The third major source of VOCs in the home is from sprays and cleaning chemicals especially the so called "air fresheners" and recently the insecticides that let out continuous sprays of chemicals into the air you breathe. Some of the companies even have do it yourself insecticide bombs! Our environment is polluted enough with pollution we can't avoid - don't go adding stuff to the air with products that you don't have to use. Don't believe the assurances of the manufacturers as to the safety of the product for spraying into the air in you home - they are very motivated by profit. I don't care what they say - their product is unlikely to be as safe as fresh air and why take the risk when you don't have to. Open the house up as much as possible, depending on the outdoor temperature, and let fresh air flow through and purge the stale air, odours and VOCs.)
Lowering VOCs and other odour inducing materials must become a higher priority for building developers and for the community in general.
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