Air ventilation is a key factor in ensuring healthy indoor air. Poor ventilation can lead to a decline in indoor air quality, moisture damage, and various health problems. This article examines the effects of air ventilation on health and how good ventilation can be ensured based on research and expert recommendations.
The importance of indoor air quality for health
Indoor air quality directly affects people's well-being and health. According to the WHO (World Health Organization), poor indoor air quality is a significant factor in the development of diseases and is associated with respiratory infections, asthma and cardiovascular diseases, among others. Factors affecting indoor air quality, such as particle concentrations, volatile organic compounds (VOCs), mold spores and humidity levels, are key considerations in ensuring a healthy indoor environment.
Indoor air pollutants and the impact of ventilation on health
Particulate matter concentrations (PM2.5 and PM10)
Fine particulate matter is particles smaller than 10 µm (PM10) and 2.5 µm (PM2.5) in size that can penetrate deep into the respiratory tract. Sources of these particles include outdoor air pollution, smoking, and indoor activities such as cooking and burning candles.
Mechanism : Particulate matter causes inflammatory reactions in the airways and alveoli. The inflammation can spread to the bloodstream and increase the risk of cardiovascular disease.
Asthma: Fine particles can worsen existing asthma and even trigger asthma attacks, especially in children. They irritate the airways and cause inflammation.
Chronic Obstructive Pulmonary Disease (COPD): Long-term exposure to fine particles is a significant risk factor for developing COPD, a progressive lung disease that makes it difficult to breathe.
Heart attack: Small particles can increase the risk of heart attack in many ways, for example by causing inflammation in the blood vessels and increasing the tendency of the blood to clot.
Research : WHO Air Quality Guidelines show that long-term exposure to fine particles increases the risk of asthma, chronic obstructive pulmonary disease (COPD), and heart attacks.
VOCs (volatile organic compounds)
VOCs are released from, for example, building materials, cleaning products and furniture.

Mechanism : VOCs irritate the respiratory tract and can trigger asthma symptoms. Long-term exposure can cause chronic inflammation and stress the cardiovascular system.
Respiratory tract infections: VOCs may in some cases increase susceptibility to respiratory tract infections indirectly, for example by irritating mucous membranes. However, a direct causal relationship (i.e. that VOCs cause respiratory tract infections) is generally not proven.
Exacerbation of asthma: Certain VOCs can worsen existing asthma. For example, formaldehyde is a VOC known to irritate the respiratory tract and thus worsen asthma symptoms.
Research : The European Commission report Health Effects of Indoor Air Quality links VOCs to respiratory infections and asthma exacerbations.
Mold spores and microbes
Mold growth and toxins secreted by microbes associated with moisture damage can cause serious health problems.
Mechanism : Mold spores irritate the respiratory tract and can trigger asthma symptoms. Long-term exposure increases the risk of respiratory infections and allergies.
Link to respiratory infections: The report shows a strong link between moisture damage, mold, and increased respiratory infections, such as cough, mucus, runny nose, and bronchitis. This link has been observed in both children and adults.
Other health effects: In addition to respiratory infections, the report also discusses other health effects, such as worsening asthma, allergic reactions, upper respiratory symptoms (e.g. nasal congestion, eye symptoms) and even some rarer diseases.
Research : The WHO report Dampness and Mould (2009) highlights that people living in buildings suffering from damp are significantly more susceptible to respiratory infections.
Carbon dioxide (CO₂) accumulation
Insufficient ventilation leads to increased CO₂ concentrations, especially in tightly closed spaces.
Mechanism : High CO₂ levels can reduce oxygen supply to the body, causing fatigue, headaches and impaired concentration.
Decision-making: The ability to make complex decisions and assess risks may be impaired.
Strategic thinking: The ability to plan long-term goals and solve complex problems may be impaired.
Information processing: The absorption and processing of new information may slow down.
Concentration: The ability to focus on a task may be impaired.
Research : Research from the Harvard TH Chan School of Public Health links high CO₂ levels to impaired cognitive performance.
Spread of infectious agents
Insufficient ventilation prevents aerosol dilution, which increases the risk of spreading respiratory infections, such as influenza and COVID-19.
Mechanism : Ventilation can spread infectious diseases when contaminated particles (droplets or aerosols) are carried from one space to another by the air flow.
General ventilation (mixed ventilation): In this type of system, the supply air mixes with the room air, which can spread contaminated particles more evenly throughout the space.
Displacement ventilation: In this system, fresh air is directed directly into the occupied zone, which can reduce the spread of contaminated particles.
Exhaust ventilation: Exhaust ventilation removes contaminated air from the space, which is important for reducing the risk of infection.
Filtration: Ventilation systems can be equipped with filters (e.g. HEPA filters) that can remove small particles, including virus particles, from the air.
Air exchange rate (number of air changes per hour): Higher air exchange rate means that the air in the space is changed more often per hour, which dilutes the concentration of contaminated particles and reduces the risk of infection.
Research : The study Role of Ventilation in Controlling SARS-CoV-2 Transmission (2021), published in the journal Nature, shows that effective ventilation significantly reduces the risk of infection.
The impact of moisture damage on health
Moisture damage is a common problem affecting indoor air quality. According to a European Commission report, the presence of mold indoors is a significant health risk. According to the WHO, up to 10-50% of buildings in Europe suffer from moisture damage, and this damage can lead to asthma, respiratory infections and chronic bronchitis.
Good ventilation is a key way to prevent moisture damage. Control systems, such as ventilation humidity control, can effectively reduce indoor humidity and prevent mold growth.
Effects of moisture damage
According to the WHO and the European Commission, up to 10-50% of European buildings suffer from moisture damage. Effective ventilation is crucial in preventing these problems.
Mechanism : High humidity promotes the growth of mold and microbes. Molds can release spores, mycotoxins (toxins produced by mold) and other volatile organic compounds (VOCs) into the air, which can irritate the respiratory tract, cause inflammatory reactions and weaken the immune system. Humidity itself can also promote the growth of bacteria and other microorganisms, increasing the risk of infection.
Asthma: Dampness and mold can worsen existing asthma and even increase the risk of asthma attacks, especially in children. They can cause airway irritation, inflammation, and increased sensitivity to allergens.
Respiratory tract infections: The report links dampness and mold to an increased risk of developing various respiratory tract infections, such as cough, mucus production, rhinitis symptoms, bronchitis, and even pneumonia.
Research : The WHO report Dampness and Mould (2009) clearly links dampness and mould to an increase in asthma and respiratory infections.
The benefits of effective ventilation
Good ventilation is an essential part of maintaining a healthy indoor environment. It not only improves indoor air quality, but also protects buildings from moisture damage and creates a more pleasant living and working environment. High-quality ventilation supports health in many ways, prevents diseases and can also promote energy efficiency.
Clean indoor air
The main function of ventilation is to remove indoor air pollutants such as carbon dioxide, VOCs (volatile organic compounds), particulate matter and other pollutants that can impair health and well-being. When there is sufficient air exchange, fresh outdoor air is brought into the interior, maintaining an oxygenated and healthy environment. This is especially important in spaces with a large number of people, such as offices, schools and public buildings.
Humidity control
The impact of ventilation on health is also reflected in indoor humidity: Indoor humidity is a key factor in indoor air quality. Too high humidity can lead to the growth of mold and microbes, while too low humidity can cause dryness of mucous membranes and skin. Well-designed and regulated ventilation helps to keep the humidity in balance, preventing the formation of harmful microbes and mold. This not only protects health but also the structures of buildings from long-term damage.
Energy efficiency
Modern, energy-efficient ventilation systems offer significant benefits by combining efficient ventilation with low energy consumption. For example, systems with heat recovery recover heat from the exhaust air and use it in the fresh supply air. This reduces the need for heating energy and at the same time carbon dioxide emissions. In this way, good ventilation promotes both environmental friendliness and cost savings.
Health benefits
Good ventilation reduces exposure to harmful substances such as particulate matter, mold spores and volatile organic compounds. This can significantly reduce respiratory symptoms, allergies and long-term health risks such as worsening asthma. In addition, fresh and oxygen-rich indoor air improves concentration, alertness and general well-being.
Overall impact
Good ventilation is an essential part of both the technical functionality of buildings and the health and comfort of users. Properly designed and maintained ventilation supports the long life cycle of a building, reduces energy costs and helps create a healthy environment for all users.
Cleaning and maintenance of ventilation ducts
Legislation and regulations
The regulations related to the cleaning of ventilation ducts have been updated several times over the years. The Decree of the Ministry of the Interior on the Cleaning of Ventilation Ducts and Equipment (802/2001) , which was issued pursuant to the Rescue Act (561/1999), was indirectly repealed on 1 January 2007. The decree was in force for three years after the new Rescue Act (468/2003) entered into force on 1 January 2004. After this, the decree in question has no longer been in force.
The current regulation is based on the Rescue Act (379/2011) , which was updated in 2018. Section 13 of the Act provides for the maintenance and cleaning of ventilation equipment:
The building owner, occupier and operator must ensure that the ventilation ducts and equipment are maintained and cleaned in such a way that they do not pose a fire hazard, with regard to public spaces and arrangements serving the entire building, as well as the premises under the control of the apartment holder.
The Ministry of the Interior also has the authority to issue more specific regulations on the cleaning of ventilation ducts that are critical to fire safety, such as the intervals, times, and content of the cleaning work.
Practical instructions
Although there are no specific intervals stipulated by law, in practice the need for cleaning depends on the purpose and circumstances of the property:
Professional kitchens and industrial facilities: Cleaning is recommended annually due to the accumulation of grease and dirt, which can cause a fire hazard.
Public buildings (e.g. hospitals and schools): It is recommended (but not required by law) to inspect and clean ventilation ducts at least every five years.
Residential buildings: The need for cleaning is assessed on a case-by-case basis. The use of filters in supply air ducts significantly reduces contamination.
Benefits of cleansing
Fire safety: Regular cleaning reduces the risk of fire, especially in areas where grease or other flammable substances accumulate.
Energy efficiency: Cleaned ducts improve ventilation performance, which reduces energy consumption.
Indoor air quality: Cleaning removes accumulated dust and possible microbes, which improves air quality.
Ventilation inspection guide
The "Ventilation Inspection Guide," published in August 2022, can be used to assess the condition of ventilation. The guide, prepared by FINVAC and other experts, presents the content of the inspection, the necessary measuring equipment, the criteria for assessing the condition, appropriate inspection intervals, and the quality assurance procedure.
An inspection is a quick and cost-effective way to check the condition, operation and need for cleaning of the ventilation system. The inspection assesses the functionality of the ventilation systems and records any defects, which are reported in the inspection report. After an approved inspection, the property can be issued an inspection certificate.
The purpose of the guide is to standardize ventilation inspections, especially in public buildings, such as schools and office buildings. It includes checklists and instructions for clients and inspectors. The information can be used to solve indoor air problems and improve energy efficiency.
Research and references
The WHO report: "Indoor air quality guidelines: dampness and mould" (2009) highlights the link between dampness damage and mould and health.
The European Commission study: "Health effects of indoor air quality" (2013) confirms the importance of ventilation in improving indoor air quality.
Ventilation Inspection Guide (2022): FINVAC and partners offer comprehensive instructions for ventilation assessment and maintenance.
Building Technology Info: "Indoor Climate and Ventilation" (2024) summarizes the key issues and recommendations related to cleaning ventilation ducts.
Good ventilation is the foundation of healthy indoor air. It removes pollutants, maintains moisture balance and supports energy efficiency, which improves both health and living comfort. The current Rescue Act sets a clear obligation to ensure the cleanliness and maintenance of ventilation ducts and equipment, not only to ensure fire safety, but also to ensure indoor air quality.
Regular maintenance – such as filter replacement, cleaning as needed, and ventilation inspections – is a key part of building maintenance and longevity. Modern ventilation technologies, such as energy-efficient heat recovery solutions, offer the opportunity to improve indoor air quality without additional energy consumption.
IVAeris Oy offers expert and comprehensive assistance in the design, installation and maintenance of ventilation. Our experts ensure that your indoor air remains healthy, safe and comfortable. Contact us, and together we will take care of the well-being of both the indoor air and your building!
WE KNOW, WE CARE & WE GET IT DONE
IVAeris Ltd.
010 206 3000