Home toxins, pollutants and indoor climate

Good air in your own four walls?

We now encounter countless chemical substances in our interiors. They come from building materials, plastics, equipment, adhesives, paints, carpets, furniture and other furnishings, cleaning and insecticides, etc.

Some of these substances have been shown to be dangerous to health, others have been found to be dangerous, but most are not known, especially with regard to long-term risks. Which substances should be considered particularly critically and carefully? What are we facing? What can you do, how can you prevent and protect yourself?

Thousands of chemical compounds have found their way into our homes. Every day, industry develops new substances, additives or auxiliaries for a wide variety of applications. Paints and lacquers, adhesives and coatings, furniture and carpets, mattresses and textiles – properties or durability, resistance to pests or flame protection, appearance or cleaning behaviour are „improved“ and propagated everywhere by new ingredients.

The journal‘ Medizinische Welt‘ reported that 5000 new chemical substances come onto the market every year, the health risks of which are virtually unknown. The thorough investigation of new substances for biological effects hardly plays a role.

Time and again the guinea pig human being is strained, only after massive occurrence of health complaints products are examined and possibly taken off the market. On the other hand, the 1992 United Nations Conference on the Environment in Rio stated: „Action should be taken when negative effects on health or the environment are suspected, even if there is still no real proof of this.

The air: outside and inside

It is now clear to everyone that our environment is becoming increasingly polluted and that more and more pollutants are poisoning people, animals and the environment. PCB and PAH, dioxin and PCP, lindane and DDT, formaldehyde and tributyltin – a multitude of formerly foreign chemical terms has become established in our everyday life. Nowhere on this planet can you find a place that would not have been afflicted by humans and their chemical products. Even at the North Pole, asbestos and DDT are found in ice, and a cocktail of fluorinated and chlorinated hydrocarbons (CFCs) and other toxic pollutants is buzzing around in the uppermost layers of the atmosphere.

Almost everyone is worried about air pollution, toxic fumes and harmful chemicals. Most people think first of emissions from cars, filling stations, airplanes, waste incineration plants or industrial plants, primarily bad outside air. Surprisingly, however, higher and more critical amounts of toxins, solvents, carbon dioxide, dust particles or other pollutants are usually found in indoor air. The Federal Health Office, for example, reported that pollutant levels in normal, unventilated living areas are higher after one hour than on main road crossings in large cities.

Federal Minister of Building and Construction Klaus Töpfer predicted in 1996 in view of the large number of chemical substances in buildings and the hazardous waste and recycling problems arising during demolition: „The demolition of a conventional house will be more expensive than construction in 20 years‘ time.

Our air to breathe

We can do without nothing less than breathing. The deep meaning of air exchange can already be seen in the fact that, for example, all ancient languages used the same word for breath as for soul or spirit. We need new air every minute of our lives and depend without ifs and buts on the fact that this air has a good quality. Everyone knows that it must be rich in oxygen, the gas that drives all our physical processes, that makes us vital and powerful. On the other hand, there must be very little carbon dioxide, a waste product of our body that we breathe out and which makes us tired and unconcentrated in increased concentrations. If the air contains toxic chemicals or excessive amounts of particles and dust, we inevitably absorb all this, we are literally polluted with every breath, our body surfaces are polluted externally and internally: The respiratory tract and skin are irritated, and through the lungs we absorb the toxins into the blood and thus our body’s interior.

Good air is essential for mental well-being and health, activity and vitality. A disturbed room climate with too few air ions, too low or too high humidity and too many pollutants, on the other hand, promote discomfort and illness, passivity and depression.

We spend most of our lives in buildings, so we mainly breathe in indoor air. If harmful substances are present in these rooms, we are permanently exposed to them, during the day and especially during the particularly sensitive and vulnerable sleep phase.

Diseases caused by pollutants

Allergies, asthmatic diseases, respiratory problems and skin diseases have been increasing for years. All these are diseases of organs in direct contact with the air around us. The German Society for Environmental and Human Toxicology (DGUHT) reports that one in four Germans has an attacked immune system and suffers from allergies. The increasing number of these diseases of civilization is an expression of the increasing accumulation of pollutants in the body.

Prof. Volker Zahn (Straubing) calls the environmental disease the little brother of cancer. Even if only a small proportion of the many cancer cases (340,000 people in Germany alone fell ill with cancer for the first time in 1997 according to the Cancer Research Centre in Heidelberg) are associated with home toxins, the figures are dramatically high.

In addition to skin and mucous membranes, more and more people are suffering from MCS syndrome (Multiple Chemical Sensitivity), a hypersensitivity to a large number of chemicals. The immune system gets out of balance, symptoms are often exhaustion and fatigue, depression, joint and bone pains, skin diseases, ear, nose and throat complaints, migraine, headaches, sleep disorders, frequent infections or rheumatic problems. MCS results from contact with chemicals and environmental pollutants. It often develops from the so-called sick building syndrome (SBS). This symptom complex occurs mainly in new or renovated buildings, often associated with air conditioning systems.

In addition to MCS and SBS, the wood preservative syndrome caused by long-term contact with wood preservatives is described as a complex clinical picture. As with SBS, the symptoms outside the living area subside quickly, often after five to eight years of constant contact.

The pollutant groups

The multitude of air pollutants and room climatic parameters are divided into six sub-items in the standard of building biology measurement technology in Pillar B „Residential toxins, pollutants, room climate“:

1. FORMALDEHYD and other toxic gases
2. SOLVENTS and other volatile pollutants (VOCs)
3. BIOZIDES and other low-volatile pollutants
4. HEAVY METALS and other inorganic pollutants
5. ASBEST and other fibres
6. ROOM CLIMATE (temperature, humidity, carbon dioxide, air ions, odours…).

Toxic for decades

Some of the pollutants are real classics; we have been dealing with them for decades and they are now generally accepted as harmful to health: The formaldehyde used mainly in particleboard as an adhesive resin component, the wood preservative pentachlorophenol (PCP), which was often additionally contaminated with dioxins, the insecticides lindane or DDT, polychlorinated biphenyls (PCB) in sealing compounds or asbestos fibres in various building materials. Although they are now either prohibited or at least restricted in their use, all these indoor toxins still contain significantly excessive and biologically critical concentrations.

The timing was similar for all these toxic or carcinogenic substances: First of all, they were used on a large scale without hesitation, cheering as the „ideal building material“. Then first admonishing voices and critical findings from science and medicine. Nevertheless, they were usually used for years or even decades, often on the grounds that there were no substitutes or that the alternatives were far too expensive, that the substances had to be used further and that they were not that bad. Finally, after more and more complaints and findings, restrictions or prohibitions were imposed.

Perhaps the most blatant example of this sequence is asbestos: Around 1900 asbestosis was discovered as a disease, 1943 lung cancer in asbestosis was recognised as an occupational disease, and since 1970 asbestos has been classified as a carcinogen in the MAK list. For years the asbestos industry has denied the risk of cancer and claimed that there are no possible substitutes. At least the use of sprayed asbestos was banned in 1979, and since 1991 Eternit has been asbestos-free. It was not until 1995 that a ban on production, import and use was finally enacted!

The same happened with pentachlorophenol: In the 1960s and 1970s, it was produced and used in huge quantities, although at that time the producing companies already had initial indications of harmful effects. Nevertheless, production and sales continued and it was not until 1989 that it was banned, at least in Germany. Other countries are still less strict today: PCP continues to be produced and used in the Third World, and even today PCP-contaminated wood and furniture can reach us.

New indoor loads

Other chemicals are comparatively new to the market, and no one knows exactly what the health effects and risks are, especially with regard to long-term risks and interactions between the pollutants.

Instead of formaldehyde, chipboards use isocyanates, for example, although no air pollution has yet been detected. The situation is different for foams, paints or adhesives containing isocyanate, where increased concentrations of these highly toxic chemicals may also occur after application.

Glycols have been used in paints or varnishes for about 15 years, primarily in water-dilutable products. These substances, which are often harmful to fruit and reproduction, are increasingly found indoors. Unlike classic solvents, glycols have higher boiling points. They only emit gases at higher temperatures or much more slowly. Thus, increased interior concentrations (e.g. after renovation work) do not only occur for a few weeks, as with solvent-based paints, but for months or years.

Siloxanes have also been found more and more frequently in interior samples in recent years. Little is known about the toxicity of these silicone-like substances, which are mainly used in furniture varnishes. Obviously, the siloxanes are the successors of the glycols.

Instead of the insecticides lindane and DDT, pyrethroids have become established, the most prominent being permethrin. It is often found, for example, in virgin wool carpets. Prof. Dr. Helmut Müller-Mohnssen (University of Munich) said of these substances: “The mass poisoning of people is accepted. Pyrethroid mosquito killers act like warfare gases and must be banned. Infections, impaired memory, nerve and movement disorders are the first symptoms. In the worst case, there is paralysis. Sometimes the effect doesn’t start until days or weeks later.” The Federal Health Office also knew as early as 1993: “Even low concentrations of pyrethroids cause health disorders in sensitive persons. Irritations of the mucous membranes, the respiratory tract and the eyes are in the foreground. In addition, it can lead to discomfort and numbness of the skin and possibly to dizziness and headaches. Children are more vulnerable than adults because of their more sensitive skin.” It is astonishing that such poisons are still permitted without restrictions indoors. The BGA: “The defence of health hazards against chemical products is not a matter for the Federal Health Office. We cannot issue warnings about certain products.”

Other frequently used and scandalously freely available insecticides, e.g. in insect bait boxes or moth repellents, are chlorpyrifos (now banned in the USA), propoxur or dichlorvos, all substances with urgent suspicion of nerve-damaging effects. With moth strips for textiles, for example, the resulting skin contact is particularly critical.

About 80 % of all water-soluble emulsion paints today, which are susceptible to microbial attack due to their high water content, are mixed with isothiazolinone-containing biocides against fungi and bacteria. The release of these contact allergens from the paints is still to be expected up to six months after the renovation. Nevertheless, the paints are advertised as “emission- and solvent-free” and “hygienically safe for indoor air”. Even colours with the “Blue Angel” may contain isothiazolinones.

In recent years, the organotin compound TBT (tributyltin) has often been in the headlines, an acutely toxic and very irritating neurotoxin. It was found in textiles, baby diapers, rubber boots or PVC floors. This means that harmful substances can be absorbed via direct skin contact as well as via house dust when PVC floors are laid over large areas.

New groups of substances, such as chlorinated organophosphonates or brominated diphenyl ethers, are also coming to the fore in flame retardants and plasticizers.

Interactions, synergisms

The extent to which the risks increase in the presence of several pollutants is decisive for the dangers and the evaluation of home toxins. Most substances do not even know what they do individually in the body, not to mention the biological effects that interact with each other. Often different chemicals seem to potentiate themselves in their effects, i.e. that two pollutants together are e.g. ten times as bad as just each for itself. Such so-called synergistic effects are disregarded in official assessments and limit values. In building biology, on the other hand, we are focusing on this problem: we do not only concentrate on individual residential toxins, but always try to analyse, evaluate and reduce as many substances as possible. We also consider interrelationships with other indoor factors such as electrosmog or fungi.

Few materials to bring in

It is almost impossible to estimate which chemicals will get into the interiors during and after the construction of a house. An attempt should be made in advance to avoid harmful substances by checking the contents or material analyses and to ensure that as few different materials, furnishings, surface coatings, paints, varnishes, adhesives, etc. as possible are used. A less number of products is also a less number of home toxins and thus more safety.

When biologically oriented products are used, the risk of contamination is considerably lower, although it should not be overlooked that irritating or allergenic substances may also be present (e.g. terpenes from natural resins).

Important: Ventilate, aerate, aerate!

New, airtight houses in particular lead to very low air exchange rates, which means that air is seldom exchanged. There is hardly any fresh outside air in our houses and apartments, and too little used and polluted indoor air is removed. The required air exchange rate of at least 1 per hour is never achieved without ample ventilation in modern buildings: instead of the necessary 100 % fresh air per hour, there is often only 10 % or even less. This means that harmful substances are concentrated indoors and often even workplace limits are exceeded.

Everyone could make a significant contribution to their own clean air through sufficient ventilation. For further improvements in indoor air, such as the removal of contaminated materials or air purification measures, expert building biology measurements are initially necessary to assess the pollutant situation.

Dr. Manfred Mierau
Graduate Biologist, Building Biologist IBN
Building biology Maes, Aachen office

Institute of Building Biology + Ecology IBN

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