Of greater concern is the use of formaldehyde in furniture components and building
products. For example, thin panels or fibres of wood are held together by formaldehyde-containing
glues to form plywood and particleboard. These pressed wood products, as they are
also called, are very popular in the housing and furniture industry because they
are cheaper than solid wood, and most importantly, don't twist and bend as solid
wood often does. They are essential materials for the manufacturers of pre-fabricated
and mobile homes.
Off-gassing or out-gassing are the terms used when the chemicals in certain substances
evaporate under normal indoor temperatures. Formaldehyde does evaporate from all
the materials I have mentioned in the previous paragraph. The good news is that the
amount that is emitted decreases gradually with time. The brand-new home with extensive
wood panelling and freshly laid carpet and vinyl has, therefore, much higher levels
of formaldehyde than a home that had a chance to off-gas for several months or years.
The level also depends on environmental factors such as temperature and ventilation.
With rising temperature more gas can evaporate from the products and the level rises
quickly in rooms that aren't well ventilated. Data from Environment Australia and
from relevant US government authorities also consistently show high levels of formaldehyde
in mobile homes/caravans.
Formaldehyde, in high enough concentrations, is extremely irritating to the eyes
and the mucous membranes of the airways. Quite predictable, the symptoms are: watery
eyes; burning sensations in eyes, nose and throat; wheezing and coughing; and asthma
attacks. Not quite so predictable, but also on the list are headache, skin rashes,
nausea, vomiting, and abdominal pain. Animal experiments also show a small risk of
developing cancer.
Formaldehyde (HCHO) is a colourless gas with a pungent odour. It is a by-product
of fossil fuel burning and is a constituent in secondhand tobacco smoke. As solution
in water it is better known as formalin or embalming fluid. The latter gives away
one of the many uses of the chemical. Its ability to react with protein makes it
useful as embalming, preserving or tanning substance, and as germicide, fungicide
and insecticide.
This is already an impressive range of practical applications, but formaldehyde is
much more widely used as a building block for a multitude of synthetic products when
combined with other chemicals.
In the modern household, formaldehyde-containing products are everywhere. Many plastic
products, glues and adhesives contain the chemical, so does the coating on fabrics
of clothes and soft furnishings to achieve permanent-press qualities.
