Indoor air - Yleistä


General information on topic

What is good indoor air like?

Indoor air is good if most users of a building are satisfied with the indoor air quality and if there are no adverse indoor air factors posing a health hazard.

Why is it important to have good indoor air? People spend 90–95% of their time indoors and breathe up to 40 cubic metres of air per day, most of it indoor air. Impurities in indoor air can cause or exacerbate allergy symptoms, irritation and lung diseases.

Impurities introduced to the indoor air in a workspace can cause health and comfort issues. People exposed to poor indoor air have been found to be more susceptible to things such as

  • respiratory tract infections
  • congested or runny nose
  • itching, burning or irritated eyes
  • hoarse or dry throat
  • general fatigue and headaches
  • fever and muscle and joint pain on rare occasions.

If there is an indoor climate issue, symptoms typically occur inside the building. Usually symptoms ease once the affected person has left the building.

In addition to causing mild irritation, impurities in indoor air can also lead to illness. Studies have shown that the onset or worsening of asthma is linked to indoor air that is harmful to health.

Many factors can cause an indoor climate issue

Indoor air quality can be impaired by things such as:

  • ineffective or insufficient ventilation for the number of persons
  • release of impurities from damp or mouldy structures
  • flooring materials’ reactions to moisture
  • volatile unhealthy emissions from construction and interior decoration materials and furniture
  • mineral wool fibres released from uncoated ventilation duct dampers and soundproofing boards
  • uncomfortable temperatures or draughtiness
  • items that do not belong to the workspaces
  • incorrect cleaning methods or inadequate cleaning.

Moisture and mould damage can be one cause of poor indoor air quality

When water and moisture gets into the structures of a workplace in an uncontrolled way, it will always cause material damage. If the moisture damage is not repaired and its cause eliminated, excessive moisture may cause microbial growth and microbial metabolites in a structure, which may result in a health hazard or risk. As a result, facilities can have an unusual odour, such as a stuffy smell reminiscent of an earth cellar. Damaged structures may release microbes, spores and pieces of mycelia, volatile organic compounds and mould toxins into indoor air.

When there is suspected or confirmed moisture damage at a workplace, the employer must determine its extent, severity and any potential consequences. The employer must take measures to repair the moisture damage.

Indoor climate issues require systematic solutions

There must be agreed procedures in place to tackle indoor climate issues, and based on these procedures the employer

  • informs personnel about poor indoor climate at the workplace
  • sets up a working group on indoor air quality, if necessary
  • consults occupational health care professionals
  • uses experts on indoor climate to review the condition of the building and to assess the results
  • disseminates information openly and promptly
  • draws up a plan and schedule of corrective actions and implements the same
  • monitors the impact of repairs on employees’ health
  • works with occupational health care to proactively support the work ability of the work community and employees.

Indoor air - Työntekijälle


Instructions for employee

If you suspect that your workplace has indoor air issues (e.g. related to the condition of the building) that cause a health risk, notify your employer and the occupational safety and health representative. Your employer has a duty to keep both you and the occupational safety and health representative up to date on any actions that have been or will be taken to address the issue. Your employer must also let you know if they deem it unnecessary to take any action.

You should let your employer and occupational safety and health representative know if you notice any symptoms that you believe could be due to poor indoor air quality at your workplace. The employer must determine together with occupational healthcare whether your symptoms are caused by the conditions at the workplace. You should also talk to your employer’s occupational health care provider about any symptoms. Occupational health care professionals can propose changes to allow you to continue working in the space that is causing you symptoms.

If your symptoms are found to be caused by poor indoor air quality at your workplace, your employer must take steps to find out the cause of the issue and eliminate it. Your employer is also responsible for ensuring that your health is not put at risk while the investigation is carried out and the remedial action implemented.

It takes time to carry out a thorough investigation, draw up a report and a plan of corrective actions, and to implement the plan. You can ask your line manager or occupational safety and health representative for updates on the situation and when solutions are expected.

The occupational safety and health authority supervises

The Occupational Safety and Health Act requires employers to continuously monitor the health and safety of the working conditions at a workplace.

The occupational safety and health authority also supervises working conditions at workplaces with regard to indoor climate. An occupational safety and health inspection can be carried out to determine whether the causes of exposure have been eliminated and how the employer is monitoring the adequacy and impact of measures taken on employees’ health. The employer must also ensure careful cleaning after repairs.

The inspector will also assess the prerequisites for continuing work. When conducting the assessment, the inspector must utilise the conclusions of reports by civil engineering and health care experts.

If your employer does not take appropriate measures to examine the cause for poor indoor air quality and to prevent exposure, you can call the occupational safety and health authority’s telephone service for advice and information.

Indoor air - Työnantajalle


Instructions for employer

Health risks caused by indoor climate must be prevented

The employer must ensure that the workplace is healthy and safe to work in. A good indoor climate can be maintained with good design and proactive building maintenance. This means, for example, that emission-free building and interior decoration materials are selected and that proper and functional ventilation is provided. Additional attention should be paid to

  • efficient engineering solutions, such as drainage
  • functional and clean ventilation system
  • regular maintenance of the building
  • cleaning.

If moisture gets into structures, the affected structures must be dried immediately to prevent microbial growth. As a rule, defective materials must be removed. The cause must be investigated and repairs carried out to prevent any recurrence of the problem.

In the event that the building is leased, the employer must contact the landlord to agree on repairs and maintenance. The employer is always ultimately responsible for their workers’ health. The employer can terminate the lease agreement if the conditions in the building are obviously putting workers’ health at risk.

Health hazards must be eliminated without delay and the impacts of the remedial action monitored

It is the employer’s duty to ensure that there are procedures in place to prevent any harmful effects on health resulting from poor indoor climate and to address any issues.

Procedure for addressing indoor air quality issues in the workplace

Graph: Addressing indoor air quality issues in the workplace.

It is the employer’s duty to

  • consult with their occupational health care provider or other health care specialists to establish whether any symptoms of workers are due to their work
  • determine in cooperation with their occupational health care provider which workers could potentially continue to work in the affected building without risking their health and on which conditions
  • determine the condition of the building reliably and thoroughly and assess its impact on the indoor climate (indoor climate review); if the employer does not have the required expertise, an expert should be used for the indoor climate review. It is recommended to involve the person responsible for property maintenance early on to find out information on any repairs that have already been made to the property. Investigating moisture and mould damage often requires various experts from the fields of construction engineering, structural physics, HVAC, microbiology and medicine.
  • carefully plan for repairs and implement them so that the repair work does not negatively affect the construction workers or others in the vicinity
  • carry out the repairs as planned
  • ensure that the facilities are properly and sufficiently cleaned after the repairs
  • follow up on the effectiveness of the remedial actions and their impact on workers’ health in cooperation with their occupational health care provider.

Setting up a working group on indoor air quality is often a good idea. In most cases, these kinds of working groups consist of line managers, representatives of the property owner and the maintenance company, the employer’s occupational safety and health manager and the occupational safety and health representative, occupational health care professionals and a representative of the affected workers. External specialists can also be invited to the working group’s meetings.

Open and timely communication is crucial

Employers can prevent rumours by communicating openly about any investigations into indoor climate issues and the progress of remedial action. If information about how indoor air quality issues are being dealt with is withheld, workers may think that their employer is not taking their symptoms seriously even if the employer has in fact taken steps to address the issue.

When investigating an indoor climate issue at the workplace, it is important to remember that details about individual employees’ health constitute classified information legislation enforced by the health protection authority on indoor climate issues. Information about individual workers’ health cannot be shared with other workers. Only health care professionals can determine whether workers’ symptoms are caused by something in their workplace.

In order to keep workers properly informed about the progress of steps taken to address indoor climate issues, employers should give them regular updates on

  • what is known
  • what is not known
  • what will be done to remedy the situation
  • when will remedial action be taken
  • what will happen next, and
  • how the impact of remedial action will be monitored.

Sisäilma - Lainsäädäntö



Occupational Safety and Health Act (738/2002)

  • Section 8 – Employer’s general duty to exercise care
  • Section 10 – Analysis and assessment of the risks at work
  • Section 32 – Structural and functional safety and health of the workplace
  • Section 33 – Ventilation of workplaces and volume of workrooms
  • Section 36 – Order and cleanliness
  • Section 37 – Airborne impurities
  • Section 40 – Biological agents
  • Section 61 – Obligations of owners, other holders or lessors of buildings

Occupational Health Care Act (1383/2001)

  • Section 5 – Occupational health care professionals and experts
  • Section 12 – Content of occupational health care

Government Decree on Safety and Health Requirements in Workplaces (577/2003, in Finnish)

  • Section 2 – Employers’ general obligations
  • Section 9 – Capacity and ventilation of workspaces

Act on the Protection of Privacy in Working Life (759/2004)

  • Section 5 – Processing data concerning health

Legislation in matters of indoor climate supervised by the health protection authority

Legislation in matters of indoor climate supervised by the building control authority

Indoor air - Oikeuden päätökset


Court decisions and precedents

According to a Supreme Court ruling (KKO:2016:99, text in Finnish), a joint municipal authority was able to demonstrate that the structural deficiencies and moisture damage in a delivery ward were not known to the joint municipal authority or predictable before midwives became ill. Moisture issues had been investigated in other wards of the hospital, but those issues could not have been caused by the same reasons as the ones in the maternity ward on the top floor. The joint municipal authority had commissioned a symptom survey and a report on moisture damage and its repair after a suspicion of mould exposure had arisen in the delivery ward. This means that the joint municipal authority had not neglected its monitoring and foresight obligations under the Occupational Safety and Health Act. The Supreme Court ruling also annulled the obligation imposed on the joint municipal authority to pay compensation to midwives who had become ill due to indoor air issues in the maternity ward.

The Supreme Court found in a case in 1998 (KKO:1998:22, text in Finnish) that a teacher had contracted occupational allergic rhinitis and conjunctivitis after working in a school between 1980 and 1993 that was later revealed to have high levels of mould and airborne mould spores as a result of leaks, structural damp and inadequate air conditioning. The Court concluded that the teacher’s health issues were occupational diseases that had been caused by long-term exposure to high levels of mould in the school building and that the teacher was consequently entitled to compensation.

Indoor air - Sanasto


Indoor air Air inside a building or a similar space.
Indoor climate A broader concept than indoor air: encompasses both indoor air and temperature conditions.
Indoor environment A broader concept than indoor climate: encompasses indoor climate, lighting, audio environment and ergonomic factors. In addition, indoor environment is impacted by other factors, such as usability, accessibility, safety, psychosocial considerations, as well as many factors relating to well-being, such as colours and materials.
Indoor air quality issue A health hazard resulting from poor indoor air quality in a building or a part of a building. Examples of causes include structural defects, inadequate maintenance, damp and mould resulting from leaks, and chemical reactions of building materials. Poor indoor air quality can also be due to organic dust, articles inside the building or emissions from processes.
Working group on indoor air quality A working group composed of specialists of different fields and representatives of the occupiers of the affected building, tasked with planning and coordinating the process by which indoor air quality issues are addressed and analysing the findings of investigations and recommended actions. The working group is also responsible for planning and coordinating how information about the process is communicated to different parties. Many local authorities and large organisations also have a coordination committee for indoor air quality to draw up investigation and communication policies, run training courses and monitor the progress of remedial action.
Indoor air quality survey Indoor air quality surveys are used to collect more detailed information about indoor air quality in connection with various kinds of research projects or if an indoor air quality issue has been identified as well as to find out more about workers’ symptoms. These kinds of surveys can also be used to study the effectiveness of any remedial action taken. The most common type of indoor air quality survey in Finland is the MM-40 questionnaire, which was developed at Örebro University Hospital in Sweden. It is important to survey everyone who can potentially be affected by the issue. Interpreting the answers requires specialist expertise. As the respondents are asked to provide details about their health, the answers are confidential. Any symptoms reported by respondents are analysed on a general level and not as specific diseases.
Indoor climate review A technical review completed by a building health inspector or a similar expert group. Aims to determine how wide-spread the indoor climate issues are and what their possible causes are. Also contains suggested measures to significantly mitigate the causes or eliminate them altogether. An indoor climate review usually covers constructional and technical factors, as well as indoor air quality and conditions. The content of the review is planned based on background information, observations from users, possible review visit, and the results of an indoor climate survey.
Exposure Refers to employees being exposed to unwanted or harmful factors, i.e. exposure agents, at work.
Evaluation of exposure conditions A thorough constructional and technical review, as well as a review of indoor air quality and building-specific factors that might impact the quantity, quality and duration of the exposure. The evaluation of exposure conditions must include an expert statement about the possible health risk or hazard posed by damaged structures.