BY PROF. GIULIANO BRESSA
Biocompatibility of materials used in construction and furniture
Various materials used in construction and furniture are the main source of indoor pollution, since the composition of commercial products contains many chemical components that cause gaseous emissions, including formaldehyde, benzene, trichloroethylene, alcohol, heavy materials, all substances whose toxicity is known to us.
A study conducted by the American EPA (Environmental Protection Agency), which lasted for over 10 years, highlighted that some atmospheric pollutants are more concentrated in closed environments than outdoors, negatively affecting our state of health. In particular, it was observed that building materials and furniture can release toxic chemical substances for long periods of time. This is the case of insulating materials based on urea-formaldehyde foam which, in some conditions, such as high humidity, emit high levels of formaldehyde for long periods of time, a substance suspected of being carcinogenic to humans.
Another important source of indoor pollution is paints used in construction and furniture. They generally contain toxic solvents such as chlorinated hydrocarbons, xylene, toluene, which are among the primary causes of pollution, being volatile organic compounds (VOC). These chemical substances have in common, in addition to high volatility, also lipophilicity, which facilitates their absorption through the skin. They therefore easily reach the central nervous system (CNS), where even irreversible lesions occur with deficits in psychic abilities.
However, there are bio-ecological paints on the market based on natural components, particularly recommended for sensitive subjects such as children and people suffering from allergic diseases. For example, there is a wide range of wood protection products of natural origin, such as beeswax, linseed oil, shellac, resins and cooked oils, which are low in harmfulness.
In order to also reduce internal pollution, it is a good idea to orient your preferences towards the use of ecological products also with regard to plasters. Lime-based paints and glue-based or natural resin-based tempera paints are suitable for this purpose. In fact, they do not inhibit transpiration and are free from side effects on health. In green building, paints prepared by combining slaked lime with water and casein, which acts as a glue, are often used. This preparation has a high capacity to absorb the humidity that forms due to condensation, thus avoiding water dripping down the walls. Furthermore, lime paints degrade uniformly, due to progressive discoloration, unlike synthetic products that show a disfiguring degradation.
As for bio-building materials, wood is certainly ideal for many uses in homes. It is absolutely the healthiest to use for structures, furnishings, floors and coverings. Its properties are many: very elastic, good insulator and absorbent towards humidity. On the other hand, materials based on cement – asbestos and urea – formaldehyde foams should be avoided which, in addition to releasing extremely dangerous substances – waterproof the house, preventing healthy transpiration and the release of indoor pollutants to the outside. On the contrary, biocompatible materials such as cork, coconut fibers and cellulose have performance characteristics of considerable importance. For example, cork is impermeable to water and gases and is a good thermal and acoustic insulator. It is also resistant to wear, fire and electricity: it is non-toxic and rot-proof. Even cellulose fiber used as a thermal and acoustic insulator is a bio-ecological material that has the advantage of constituting a valid form of recovery especially from an environmental point of view, based on the recycling of discarded paper products.
As for floors, in addition to wood, linoleum is used in green building, which is made up of a homogeneous mixture of linseed oil, mineralized resins (coppals), vegetable resins and glycerophosphate resins mixed with inert materials such as wood flour and cork.
The mixture obtained is pressed onto jute and left to dry for several weeks.
Linoleum is an inert product, it does not emit harmful substances, it is a good insulator and easy to clean, resistant and economical. Another material for covering floors is carpet, which is usually made of a polyamide surface layer. However, this covering is not recommended for those who suffer from allergies as it is a real receptacle for dust and mites. Furthermore, carpet absorbs smoke and odors and then releases them slowly. Finally, it constitutes an excellent breeding ground for mold and pathogenic microorganisms as humidity stagnates there.
If you still want to cover the floor with carpet, it is advisable to choose the natural one without using synthetic glues for laying, taking care not to walk on it with shoes, not to smoke and not to keep pets in the house.
