The importance of good indoor air: a smouldering storm or a gentle breeze?
We've all been there: you're sitting in a meeting and everything is going well. After a while, you feel a little tired and your concentration wanes. Then you get up briefly, leave the room and come back a few minutes later. And when you enter the room, you notice it: the air is stale, heavy and has a strange odour.
We humans do not have an in-built sensor with which we can recognise the Air quality can measure. We only feel the effects it has on us. Only then, or as described in the example above, when we have a direct comparison, do we consciously perceive the room air.
If the indoor air is only of unhealthy quality for a certain period of time, the body can neutralise this relatively quickly. However, if you are in such rooms for a longer period of time, this can not only affect the body, but also the psyche in the form of Sluggishness, depression or lack of concentration.
This must be counteracted, otherwise an initially mild breeze will quickly turn into a smouldering and persistent storm.
What exactly is a "good indoor climate"?

Simply put, a good indoor climate means good air. But what is "good air"? What should you pay attention to and are there certain standard values that you should follow when building?
Good air is characterised by a low content of these things:
- Dust particles
- Pollen
- Bacteria
- Mushrooms
- Mould spores
- Viruses Gases
- Volatile organic compounds
- Nitrogen oxide
- Carbon monoxide
Air quality is also influenced by temperature and humidity.
As a rule, an optimum indoor climate is achieved with a relative humidity of 50 per cent and about 20 degrees Celsius room temperature. However, these values may vary depending on the room and room utilisation.
The consequences of poor indoor air quality
A good, healthy indoor climate and good indoor air are essential for the physical well-being is of great importance. A wide variety of Symptoms can occur - from poor concentration and headaches to nausea and irritation of the eyes, respiratory tract and mucous membranes.
A healthy indoor climate should therefore not be underestimated. Especially in public buildings, particularly schools, nurseries and hospitals, where children or at-risk groups are present, a good indoor climate with a healthy indoor climate is essential. the lowest possible concentration of pollutants to pay attention.

as "Sick Building Syndrome", or SBS for short, usually describes non-specific complaintsthat occur in people who have been in a building for a long time. These are usually offices.
The symptoms include Irritated eyes and mucous membranes, headaches or allergies. The cause is not entirely clear, but it is suspected to be a Context with a increased concentration of pollutants. According to measurements by the Federal Building Ministry, this is six to eight times higher than in the outside air

A brief digression: Air pollution then and now
In the 19th and 20th centuries, these were mainly microbial contaminants and combustion products from lighting and heating. Nowadays, pollutants in the air mostly come from organic compounds from building materials and furnishings, but they can also be of natural origin.
They can accumulate indoors due to low air exchange in the house. Improved thermal insulation and the installation of airtight windows, such as those installed since the oil crisis in the 1970s, can contribute to this. According to the WHO, we are thus exposed to more environmental pollutants than through the intake of food, water or outdoor air.
What pollutants can be found in indoor air?
Pollutants can enter indoor spaces in different ways and the indoor climate. On the one hand from outside through road traffic, but also from the inside. Frequent sources here are cigarette smoke, gas cookers, but also various building materials or processing methods, from which the problematic substances either dissolve immediately or over time, are released into the air and thus cause the Negatively influence the indoor climate. We have summarised what all this can be here:
Pollutants that are difficult to remove

- Nitrogen dioxide (NO2) : NO2 is a colourless gas that occurs naturally in the atmosphere. It is mainly produced by Combustion processes. However, NO2 can occur in large quantities indoors as a result of industrial emissions. Nitrogen dioxide is a Irritant gas and can above all lower respiratory tract.
- Radon: You might not think about this noble gas when you start building. It occurs naturally in rocks such as granite or limestone. Not only can it enter indoor spaces from the ground, but certain concentrations of the carcinogenic noble gas can also be found in mineral building materials.
- Volatile organic compounds (VOCs)VOCs are chemicals that evaporate easily from surfaces and dissolve in liquids. They are found in many products and materials. Some examples are solvents, paints, adhesives, cleaning agents, pesticides, fuels, plastics and rubber. Loose objects can simply be removed from the room. It is more difficult to remove permanently installed building materials, which then require renovation and remediation. One of the most common VOCs indoors is formaldehyde.
Easy to remove pollutants

- DustEveryone knows it, everyone has it, everyone tries to minimise it - house dust. Around 6 milligrams of dust per square metre form in a normal home every day. We shed almost 2 grams of dead skin cells every day. However, dust can also be brought indoors by traffic or agriculture. Nevertheless, the following applies: Ventilate regularly for several minutes, as there is less dust outside than indoors. Regular vacuuming can help.
- Pollen and mites: House dust mites embedded in mattresses and textiles can trigger some allergies. However, there are now also allergy-friendly options that can provide relief. Regular vacuuming and cleaning keeps the mite count low. Air purifiers, special filters in hoovers and ventilation when there is less pollen in the air (in the morning or evening) help with pollen counts in spring.
- Tobacco smoke: Around 40 substances in tobacco smoke are harmful to health and are even considered carcinogenic. It is not only the smoke that is inhaled directly that is dangerous, but also the smoke that is released into the air. So think carefully about whether you want to smoke in your home or whether you'd rather take it outside.
- Odours: They are not only unpleasant, they can even lead to health problems. The first step is therefore to find the source of the odour. It could be something that is easy to remove, such as leftover food or fresh paint, or the first signs of leaks in the room or mould or rotting of building materials due to damp. Regular ventilation also helps to combat everyday odours.
- Carbon monoxide (CO): CO is a colourless and odourless gas that is released during incomplete combustion processes. It can enter the interior of the home primarily through leaking ovens, gas cookers or fireplaces. Car exhaust fumes can also lead to increased concentrations in car workshops or garages. In high doses, carbon monoxide is life-threatening. Especially if you have a fireplace, a stove or a gas boiler, you should use a carbon monoxide detector for your own safety. Then you will always know immediately and keep an overview.

Formaldehyde, also known as methanal, is a Colourless and water-soluble gas with a pungent odour. In nature, this gas can be produced by incomplete combustion of carbon-containing objects. In liquid form it is known as Formalin used as a disinfectant in hospitals.
There are countless sources indoors from which formaldehyde can escape and enter the indoor air. It represents a Basic substance for chemical compounds which are necessary for the production of chipboard, adhesives, varnishes, paints, etc. Formaldehyde is considered Harmful to health and even carcinogenicas it can cause headaches and discomfort and irritate the mucous membranes and respiratory tract. Tips, how you can neutralise formaldehyde, we have given you in this advice article compiled.
How do I ensure good indoor air?
Safe and secure - that's how you want to feel in your home. To ensure that this is really the case, you should pay attention to more than just the visual appearance before you start building. The basic rule here is: build qualitatively instead of cost-intensively renovating. This is because different pollutants can seep into the air from walls, floors and furniture.
Even if the house is already standing, it is often possible to improve the indoor air with just a few household remedies before health problems arise.
We have summarised a few tips for you on what you should bear in mind when building a house.
Step 1: Think about the indoor air before building the house.

Building a house is probably one of the most important and biggest decisions in life. Therefore, in addition to the financial aspects, you should also take a closer look at the property you are considering and ask yourself the following questions:
- Where exactly is the property located and what is in the immediate vicinity?
This question can be used to identify potential air pollutants or air pollution before construction begins. In addition to industry or road traffic, agriculture can also cause a certain amount of air pollution, which can later enter indoor spaces. - What is the substrate like?
To avoid any unpleasant surprises later on, you should take a closer look at the subsoil. The noble gas radon can be found in rocks such as granite or limestone and later rise up into the house from below. If the property is located in a rather swampy area, a good foundation or basement is particularly important. Therefore: Clarify the groundwater level with the builder in advance. You should also check for any problems with moisture after moving in so that any damage can be repaired immediately before too much moisture can penetrate the masonry. - What was there before?
It's not just us humans who often carry contaminated sites around with us, but also properties and houses. Therefore, have them checked for possible residues such as oil or asbestos. - Are there any structural restrictions or prohibitions?
You should also find out in advance about possible restrictions. It is best to consult with experts. For example, there are so-called drinking water protection areas in zones I and II. Here, for example, the use of geothermal energy is prohibited under the ordinance on protective regulations.
Step 2: Decide in favour of good indoor air during construction

Once everything is in order with the plot, building can begin. The rule here is: if you build healthily, you can live healthily. The right building materials are therefore essential, as this prevents pollutants from entering the indoor air in the first place. Natural materials are often good alternatives, but here too a closer look is often necessary: Natural building materials may have been treated with chemicals such as wood preservatives or insecticides. Eco-certifications such as the Blue Angel, EU Eco-Label, natureplus or Emicode can help with the selection of materials, but so far there is no standardised regulation. TÜV certificates can also be helpful.
What materials are available for healthy building?
- Wood:
Wood has a positive effect on the indoor climate in several ways: it is anti-allergic, anti-electrostatic and antibacterial. Wooden furniture therefore does not attract dust or irritate mucous membranes. Wood fibre insulation boards with climate chambers, for example, are a healthy and ecological alternative to plasterboard. Wooden furniture also stores CO₂ over the long term and is climate-neutral. It is only necessary to pay attention to gluing, varnishing or sealing. - Loam and clay:
For thousands of years, loam and clay have been used as a universal building material (such as here by our partner Romberger) is used. Whether as fired clay bricks, clay building boards or as a plaster material - the ecological balance speaks in favour of clay. This natural material offers many advantages: easy processing, good heat storage, almost no waste, regulates humidity and thus makes a positive contribution to the indoor climate. - Natural stone:
Natural stone can be used both indoors and outdoors. It creates a special atmosphere and is suitable for use as flooring, wall panelling or worktops. Natural stone stores heat, is extremely durable and stable. - Lime:
Lime has also been used for thousands of years. It is harder than clay and can be hydrophobised without any chemicals. This means that high-gloss, water-repellent and seamless surfaces can be created. Lime is also a good choice for the indoor climate. Thanks to its alkaline pH value, there is no risk of mould and it also makes a positive contribution to regulating the humidity in the room. - Brick:
As bricks are fired at very high temperatures and are pure and inorganic materials, there is no risk of biological organisms binding to them and growing. Brick buildings also do not release any gases or allergens - ideal for a good indoor climate. - Straw, hemp and plant fibres:
The potential uses of straw, hemp and other plant fibres are enormous. Straw, for example, has been used as a lightweight aggregate for centuries. These materials are ideal insulating materials, are suitable for sealing windows and doors and are suitable building materials for ensuring a good indoor climate. The materials offer many advantages: they are breathable, recyclable, free of harmful substances and help to regulate humidity. Compared to sheep's wool, however, more material is required, which makes it more expensive to use. Hemp also has no air-improving properties. In the event of water damage, sheep's wool can absorb around 30 per cent without loss of thermal insulation and then dry out again. Hemp must be replaced in such cases, and there is also a risk of mould growth - Sheep's wool as a miracle cure:
Fire protection, indoor air, acoustics, air quality, recycling, thermal insulation - sheep's wool stands out in all areas. Sheep's wool is the ideal choice, especially when it comes to the indoor climate: thanks to its basic protein building block keratin, the material is able to absorb toxins such as Absorb and neutralise formaldehyde Mould also doesn't stand a chance. Due to its hygroscopic properties, sheep's wool can absorb up to 33 % of its own weight in moisture, but the thermal insulation remains intact.
Step 3: 7 measures that help to improve the indoor air even after the house has been built

If your house is already standing and the concentration of pollutants is not too high, you can improve the indoor air with relatively simple and inexpensive tricks. We reveal our 7 best tips:
- Fresh breeze: Proper ventilation is often the simplest, but also the most effective solution for improving indoor air quality. However, the following applies: airing in bursts is better than continuous ventilation. Tilted windows do not exchange air in the interior. It merely cools down. This also increases the risk of mould. Ideally, you should ventilate the room three to four times a day for five to ten minutes to allow fresh air into the room and replace the bad air. IMPORTANT: Even in winter, when the cold air feels uncomfortable at first, don't do without regular ventilation! Opening the window in the living room or bedroom for a few minutes can work wonders.
- No chance for dust: Regular dusting and vacuuming not only has the effect of keeping everything spotless, it also ensures that less dust gets into the room air. Many allergy sufferers also swear by so-called HEPA filters in hoovers. These filter even the smallest particles such as fine dust, allergens or pollen and spores from the room air.
- It all depends on the remedy: Solvent-free cleaning agents generally do not contain any aggressive ingredients that can enter the room air. There are now many organic cleaning agents on the market. Home remedies should not be underestimated either.
- Less is more: The more furniture, upholstery, curtains and decorative items, the more "dust catchers" and "dust producers" there are in the room. So if you can get rid of some things, this can also contribute to better indoor air.
- It's so green: Houseplants are beautiful to look at, bring life and colour into the room and also purify the air. Plants filter the pollutants from the room air and release clean air again. Some can even break down chemical pollutants. One plant per nine square metres is the ideal benchmark here. So how about a common ivy, a dragon tree or a peace lily? These three houseplants are considered perfect air purifiers.
- Hot or cold: Room temperature also plays a role in air quality. 19 to 22 degrees Celsius is ideal for healthy living. This makes it more difficult for spores or other bacteria to spread.
- Too dry or too moist? To avoid mould, you need to pay attention to the humidity indoors. The perfect indoor humidity level is between 40 and 60 per cent. Mould not only looks unattractive, it is also harmful to health. The bathroom in particular, but also the bedroom, is susceptible to mould.
Improving indoor air - our conclusion

The role of the indoor climate for our health is often underestimated. Whether in the bedroom, home office or kitchen, we often have a rude awakening in our own home: Coughs, headaches, eye irritation, etc. can be the consequences of this negligence. There are a few things you can do before and during construction to ensure healthy indoor air right from the start. But simple measures can also be taken afterwards to ensure that the indoor climate improves again: valuable tips, such as placing "good" houseplants in the home, help to improve the indoor climate and live healthily.
After the new school building went into operation, the bad discovery followed: far too high formaldehyde levels in the interior rooms! Sheep's wool made it possible to avoid dismantling or demolition.
Client: Frauenfeld Felben-Wellhausen schools; refurbishment consultancy: Bau- und Umweltchemie AG
Whether modern, angled or classic, whether as a bungalow or multi-storey: the 'Scandinavian Blockhaus' team produces log houses for every taste, well insulated with ISOLENA sheep's wool insulation.
Planning and realisation: Scandinavian Blockhaus BauGmbH
A Romberger house combines the advantages of prefabricated production with the desire for individualised living. In solid construction and exclusively with natural and ecological building materials such as our sheep's wool insulation and our Siltentum acoustic felts, healthy dream homes are created.
Owner and client: Romberger Fertigteile GmbH, Exhibition location: Haid show house park