Plants can remove impurities in the air and help achieve a better indoor air quality.

What is Good Indoor Air Made of?

What are the factors that actually determine whether indoor air is good or bad?

Poor indoor air quality forces people to leave their homes and offices. These cases are often related to water and mold damages, but there are several other factors contributing to the possible problems in the air.

Good indoor air does not cause any symptoms to the people occupying a building. It feels comfortable, and makes it possible to work more efficiently. The air quality of a building is affected by the building’s age and condition, possible water and mold damages, air ventilation, humidity, temperature, and other environmental factors, such as pollution and exhaust fumes.

Several variables behind indoor air quality

Indoor air consists of the combination of several different variables. The international WELL-standard lists 29 of these. The list includes e.g. air ventilation effectiveness and filtering, safety of the building materials, cleaning protocols such as equipment and cleaning agencies used, and prevention of any excessive chemicals such as tobacco and pesticides. Three main factors could be highlighted from the listing:

Air impurities

The impurities in the air originate from people, outdoor air and, for example, building and furnishing materials. These are e.g. volatile organic compounds, particulate matter, and harmful microbes such as molds.


Optimal air humidity indoors is ~45 %. Air that is too dry irritates airways, mucous membranes and skin, and it has also been linked to sick building syndrome. A good level of humidity also binds particles and impurities from the air, while a level too high exposes buildings to water and mold damages instead.


Optimal temperature indoors is 20–25 degrees celsius. Temperature also affects humidity: too warm makes the air feel stuffy and dry. Too cold, in turn, feels uncomfortable and could be a health risk, and it might also increase the time needed for moisture to evaporate, therefore exposing buildings to water and mold damage.

Did you know? Females prefer air few degrees warmer than males  – that is, around 24–25 degrees – as they perceive temperatures a little differently.

Plants can remove impurities in the air and help achieve a better indoor air quality.

Small actions could lead to a big impact

Indoor air quality can drop temporarily during renovation or new furniture. Newly built houses release more chemicals to the air, but the amount drops in time if air ventilation functions properly. Cleaning products can also raise the chemical burden indoors, as they contain compounds that evaporate to the air, such as perfumes.

Increasing air ventilation is often enough to secure clean air. Sometimes, however, it might be necessary to get rid of the furniture or materials causing harm, or at least let them ventilate outdoors. Humidity might also rise too high temporarily during e.g. drying laundry, if the air ventilation is not effective enough.


5 tips for improving indoor air quality:

  • Taking care of proper air ventilation is important for removal of chemicals, carbon dioxide, and excess moisture. Keep the ventilation of your windows open  throughout the year, and make sure that the mechanical air ventilation functions as it is supposed to.
  • Installing outdoor air filters prevents pollution from entering indoors.
  • During renovation or even simply decorating, pay attention to the materials that are low polluting and non-dusting. Some products tell in their label, if they are a non-VOC product.
  • Cleaning regularly with non-perfumed, mild (non-antibacterial) products and avoiding smoking indoor or near the building help to reduce chemical burden indoors.
  • Plants are known for their ability to remove pollutants. Traditional potted plants however won’t filtrate the air effectively through their roots, where the air purifying roots with their microbiome is. In the Naava greenwall, about 60 m3 of air filtrates through the roots every hour!

Moisture and mold damage are always health risks

In preventing mold and moisture damages, taking care of the indoor air quality is essential. If the damage is already done, bigger actions need to be taken, as they are always extremely harmful for the health and wellbeing of the occupants. Damages need to be examined by professionals, who then prepare for the necessary actions.

Even after repairs, thorough cleaning should be done – during the renovation, a lot of microbes will be released to the air and continue to cause damage. It is important that people suffering from symptoms caused by molds are able to spend their time in buildings where recovery is possible. Exposure to mold for too long, or other indoor air problems may lead to permanent damage for the body.

Contact us

Our experts will help design your space, old or new. Our consultation is always free! Send us a message and we will be in touch with you.