What are the reasons for problems in indoor air quality? See a comprehensive list of indoor air quality risk factors at home and in the workplace

Uniq kodin olohuoneessa

Several factors influence indoor air quality. Some of them may come as a surprise. Indoor air quality problems may cause various symptoms, illnesses and chronic health problems. See a comprehensive list of indoor air quality risk factors in spaces where we spend the majority of our time.

Room dust

Room dust is constantly released into the air from home surfaces, textiles, furniture, clothing, plants, insects and the skin of both people and pets. Room dust
easily predisposes inhabitants to symptoms resulting from indoor air. Regular and careful cleaning reduces the number of particles, but it also spreads the dust from the surfaces into the indoor air.

Animal dust

Pets are a joy, but they also burden indoor air. The hair, feathers, dander and other particles from dogs, cats, rodents and birds can cause allergic symptoms. In addition, for example litter, hay and bedding affect indoor air quality.


Pollen causes allergy symptoms for approximately a fifth of people in Finland. The warming climate has prolonged the pollen season from February to August, causing allergy symptoms for up to 7 months each year. As much as 80% of impurities in outdoor air find their way indoors through doors, windows and ventilation.

Volatile organic compounds from normal living

Human metabolism produces carbon dioxide and odours that are released into the air. Stuffy air, impurities and strong odours cause allergic symptoms in the respiratory system, eyes, as well as other symptoms. Air pollutants include fumes from cooking in particular, PAH compounds from burning candles, as well as carbon monoxide and carcinogens in tobacco smoke.


Perfumes, shampoos, soaps and other cosmetic products are created to please the senses, but even pleasant fragrances may cause allergies and bothersome symptoms for anyone sensitive to them. Cosmetics also include microplastics that are harmful to the respiratory system. An estimated 2–3% of people in the western world are sensitive to fragrances. Symptoms include a number chemical sensitivities and contact dermatitis.

Detergents and cleaning agents

Many chemicals used for general cleaning purposes are toxic: dangerous if ingested, and harmful for respiration. As detergents and cleaning agents are usually handled on a daily basis, they play a major role among risks to indoor air quality in homes and workplaces.

Chemicals from textiles

Various chemicals are used in the manufacturing and finishing of textiles, furniture and clothing to prevent mold and creasing and to facilitate easy care. These chemicals are extracted to air for a long time when the fabrics are used. In the EU countries, textile product safety is controlled by law. In Finland, the Customs Laboratory finds up to 14% of textiles to be in violation of the regulations every year.

Compounds from candles

Burning candles produce PAH compounds, which are carcinogenic and toxic to cells. These particles can cause harm particularly to people suffering from cardiovascular and respiratory diseases and young children.

Green plants and potting soil

For many, green plants are integral to comfort at home and in the workplace. Plant fluids and flower scents may cause symptoms for multiple chemical sensitivity sufferers. However, potting soil is the most harmful agent in terms of indoor air quality, because mold spreads easily in a moist environment.

Chemical compounds from building materials

Chemical compounds are used in building materials, such as building slabs, mineral wool, paints and glues. Due to emissions, a mandatory airing period has been imposed on new buildings, This period can last up to a number of months. Compounds emitted by the materials, aldehydes and ammonia, often have a very strong odour and may cause serious symptoms for the most sensitive.

Mineral wool fibres

Mineral wool fibres, such as rock wool and glass wool, cause problems for indoor air quality if they are freely released into the air. These materials are commonly used for thermal insulation and sound insulation purposes and to improve acoustics. Mineral wool fibres became more common when the use of asbestos fibres was banned.

Particles and gases spreading through ventilation and structures

Do you live in the city centre? Is your workplace situated on a road with heavy traffic? Did you know that up to 80% of outdoor air impurities end up indoors through doors, windows and ventilation? For example exhaust gases from cars, wood combustion gases and insalubrious fine particles may case symptoms indoors.

Traffic particles and gases

According to the WHO, 90% of the world's population breathes dangerously polluted air. Humans are most exposed to outdoor air impurities indoors. Of traffic pollutants, carbon monoxide, hydrocarbons, soot particles and NOx cause symptoms. Pollutant levels are particularly high in city centres and industrial locations.

Particles and combustion gases from burning firewood

Fireplaces and wood-burning sauna stoves create a special atmosphere. However, smoke from burning firewood is among the most significant pollutants in residential zones because burning wood emits fine particles and carcinogenic PAH compounds, which are toxic to cells. Particles from burning firewood cause harm particularly to people suffering from cardiovascular and respiratory diseases and young children.


Radon is an odourless, tasteless and colourless radioactive gas, which is found everywhere in the Finnish soil. Second only to smoking, it is one of the most common causes for lung cancer. Because you cannot see or smell radon and it does not cause any symptoms, the only way to detect radon levels at home and workplace is to measure it. The Radiation and Nuclear Safety Authority STUK measures radon levels around Finland and maintains a list of the municipalities obligated to conduct measurements and all areas where the risk of radon is high.

Gaseous impurities caused by water damage, mold fungi and bacteria

Mold is a common cause of severe problems in indoor air quality. Molds and microbes grow in structures and on the surfaces of construction materials when sufficient moisture is present. Water damage is a major root cause of mold problems.

Mold spores spread easily into the air and all over the body in respiratory air. They cause not only allergic rhinitis and farmer's lung, that is, allergic alveolitis, but a range of other severe symptoms as well, including respiratory and skin symptoms, nosebleeds, recurring flu, headache, muscle and joint pain, recurring fever, memory problems and nausea.

Mycotoxins from microbes

Microbial growth begins from water damage to structures. Insalubrious microbes, mold spores and actinomycetes, fragments of mycelium and microbial metabolites, such as VOCs and toxins, are emitted into indoor air. Like the gases produced by molds and bacteria in their metabolism, mycotoxins can cause severe symptoms.

Bacteria and viruses

You breathe in 10,000 litres of air in 24 hours. The most important thing you put in your mouth is respiratory air. Many recurring flus originate from problems in indoor air quality. In public premises where many people move about, the carbon dioxide load increases as does the number of bacteria and viruses in indoor air.


Microplastics are created from the degradation of plastic waste. Researchers estimate that by 2050, the seas will contain more plastic than fish, when measured by weight. Microplastics are not only problematic in waterways. The University of Turku Archipelago Research Institute has detected large amounts of microplastics in outdoor air, and it penetrates the human body through respiratory air. Microplastics are also used in house paints, clothing and cosmetics.


Ozone is the most reactive gas affecting the respiratory organs. It irritates the eyes and mucous membranes of the respiratory tract and has a strong smell. The slightest amounts of ozone are dangerous to humans. UV lamps and air purifiers containing electric filters produce ozone. Also the use of copiers and laser printers produces ozone to indoor air at home offices and other workplaces.

Interested? Read more.

Breathe in UniqAir and feel the difference.

Clean air for homes Clean air for workplaces

Read also

UniqAir -ilmanpuhdistimet - artikkelit

A German study: Opening windows not enough to clear the virus from interior air

Read more
UniqAir -ilmanpuhdistimet - artikkelit

New research result on lowering the viral load of spaces with UniqAir air purifiers

Read more