Indoor Air Illness (Sisäilmasairaus) in Finland and CIRS

Indoor-air symptoms (sisäilmaoireet) are symptoms a person links to a particular building, such as a home, school or workplace. Common examples are airway, eye and skin symptoms, headache and fatigue. Their cause, or the link to the building, is not always known [1].

In Finland, “indoor air illness” (sisäilmasairaus) and “mould illness” (homesairaus) are everyday words, not medical diagnoses. Finland’s 2024 treatment recommendation states that there is no specific “indoor air illness” [1]. It says symptoms arise from many factors at once. Moisture damage is a risk mainly for the airways and asthma. Long-lasting, widespread symptoms are explained largely by functional mechanisms [1].

CIRS (Chronic Inflammatory Response Syndrome) is a different model. It describes an inflammatory illness after exposure to water-damaged buildings, with its own laboratory tests [2].

People who fall ill in a damp or mouldy building in Finland use many words: sisäilmasairaus (indoor air illness), sisäilmaoireilu (indoor-air symptoms), homesairaus (mould illness), ympäristöherkkyys (environmental sensitivity) and kemikaaliherkkyys (chemical sensitivity, MCS). Only one of these is a medical term with its own diagnostic code. This article explains each term, what Finnish medicine says now, how CIRS differs, and what you can do if you suspect your home or workplace.

What do sisäilmasairaus, homesairaus and the other terms mean?

The words overlap in everyday speech, but they mean different things to doctors.

Term (Finnish)	What people usually mean	Status in Finnish medicine
Indoor air illness (sisäilmasairaus)	“I got ill from the air in a building”	Not a diagnosis. The 2024 recommendation says no specific indoor air illness exists [1].
Indoor-air symptoms (sisäilmaoireilu, sisäilmaoire)	Symptoms that appear in a particular building	The official term: a symptom the person links to a building, without a known cause or proven causal link [1].
Mould illness (homesairaus, “mould house illness”)	Illness caused by a mouldy home, school or workplace	Not a diagnosis. The 2017 Current Care guideline stated that no defined “mould house illness” exists; moisture damage is one risk factor for respiratory symptoms and asthma [3].
Environmental sensitivity (ympäristöherkkyys)	Reacting to smells, chemicals, mould or electricity that others tolerate	A recognised condition, classed as a functional disorder. Finland uses the symptom code R68.81 when the criteria are met and functional limitations are significant [1].
Chemical sensitivity, MCS (kemikaaliherkkyys)	Symptoms from perfumes, cleaning products or traffic fumes	Finnish guidelines do not treat it as a separate illness but as one form of environmental sensitivity [1].
CIRS	A multi-system inflammatory illness after exposure to a water-damaged building	Not part of Finnish guidelines. Described and studied mainly by Dr Ritchie Shoemaker’s group [2, 4].

The term MCS (multiple chemical sensitivity) comes from a 1999 consensus definition [5]. It describes a chronic condition in which:

• symptoms come back in the same way with low-level exposure to many unrelated chemicals
• symptoms affect several organ systems
• symptoms improve when the triggers are removed

How does Finnish medicine view indoor-air symptoms?

Finland’s main guidance changed in 2024. The old guideline came from Current Care (Käypä hoito), Finland’s national clinical guidelines, written by the Finnish Medical Society Duodecim. Its title was Kosteus- ja homevaurioista oireileva potilas (“The patient with symptoms from moisture and mould damage”).

The new recommendation was written by a working group set up by the Ministry of Social Affairs and Health. The group included researchers, clinicians, patient representatives and social security experts [1].

What does the 2024 recommendation say?

Its main positions, stated fairly:

• Symptoms are common and usually mild. A survey in 2022–2023 asked about indoor-air symptoms at work in the past year. About 16% of working-age women (one in six) and 8% of men (one in twelve) reported them. At home the figure was about 4–5%, or one in 20–25 people [1].
• Many factors act at once. Three kinds of factors affect whether symptoms appear, last and get worse [1]:
  • the building: ventilation, temperature, dry air, moisture damage, dust
  • the person: health, stress, sleep
  • the community: the work community, worry, the media
• Moisture damage is a real risk, mainly for the airways. A moisture-damaged building connected to the indoor air is a risk factor for respiratory symptoms. It is also a risk factor for developing asthma or making it worse [1]. The recommendation sees weaker evidence for general symptoms such as fatigue [1]. It also notes that the levels of mycotoxins (mould poisons) measured in water-damaged buildings are below toxicological safety limits [1].
• Functional mechanisms explain much of the long-lasting symptoms. “Functional” (toiminnallinen) means that the nervous system and stress system have become sensitised. Ordinary sensations then feel stronger, and the symptoms keep themselves going. The recommendation describes a continuum. Functional mechanisms can play a part even in mild symptoms and can dominate the most severe cases [1].
• Environmental sensitivity is an umbrella term. Under the current medical view, separate “electrical”, “chemical” or “indoor air” sensitivities do not exist. There is one environmental sensitivity. It is estimated to affect under 0.2% of Finns, fewer than 2 in 1,000 [1].

What is easy to miss in the debate?

First, the recommendation states that even severe functional indoor-air symptoms are not a mental disorder and are not caused by one [1].

Second, it insists that the patient be listened to carefully, given enough time, and supported whether or not a diagnosis is found [1].

Treatment, according to the recommendation [1]:

• treating any diagnosed illness, such as asthma, by the usual guidelines
• supporting your ability to function in daily life
• for symptoms that point to environmental sensitivity, approaches such as internet-based therapy for bodily symptoms, psychophysical physiotherapy (physiotherapy that works with both body and mind) or behavioural therapy

The recommendation also asks that faults found in a building be repaired without delay. It notes that there is no research evidence for so-called “extra-clean” rooms [1].

Not everyone agreed. In the public consultation, trade unions and private individuals criticised the draft for emphasising functional disorders and playing down health harms. Some research bodies argued the opposite [6].

How is CIRS different?

CIRS is a model developed by the American physician Ritchie Shoemaker. It goes like this:

Treatment starts with ending the exposure and continues with the stepwise Shoemaker protocol [2].

So the two views differ in what they think is going on. The Finnish recommendation describes a symptom picture with many causes. For long-lasting symptoms, the brain’s threat and stress systems play a central role. CIRS describes a specific inflammatory illness in a subgroup of exposed people. Shoemaker’s group says it can be identified with specific tests [2].

Is there a similar debate in Finland?

Yes. Two Finnish proposals point in a similar direction to CIRS:

• Valtonen 2017. The Helsinki infectious diseases specialist Ville Valtonen proposed clinical criteria for a “dampness and mold hypersensitivity syndrome”. The criteria were exposure history, frequent infections, building-related symptoms, chemical sensitivity and scent sensitivity [7].
• Hospital staff 2020. In a questionnaire study, nurses and midwives from a moisture-damaged Finnish hospital reported fatigue, brain fog and chemical sensitivity far more often than a comparison group [8].

Neither proposal has been adopted in the Finnish recommendation. The questionnaire study was small and relied on what people reported themselves.

Where do the Finnish guidelines and the CIRS model agree and disagree?

Question	Finnish recommendation (2024)	CIRS model (Shoemaker)
Is there a specific illness?	No specific indoor air illness; environmental sensitivity is a functional disorder [1]	Yes, CIRS, in a genetically susceptible subgroup [2]
Can moisture damage harm health?	Yes, mainly airways and asthma [1]	Yes, and in susceptible people the whole body [2]
Why do symptoms continue after leaving the building?	Sensitisation of the nervous and stress systems, worry, avoidance [1, 16]	Ongoing inflammation; re-exposure to low levels keeps it going [2]
Can tests show the cause?	No laboratory test can link symptoms to a building [1, 3]	VCS and blood markers support the diagnosis [2]
Fix the building?	Yes, repair faults without delay [1]	Yes, ending exposure is the first step [2]
Avoidance	Long-term avoidance can narrow life and maintain symptoms [1, 10]	Strict avoidance of water-damaged buildings is essential [2]
Treatment	Usual care for diagnosed illnesses, support for functioning, psychological and physical rehabilitation [1]	Stepwise Shoemaker protocol [2]

They agree on more than the public debate suggests. Moisture damage should be repaired. The symptoms are real. The patient deserves to be heard. Other illnesses must be ruled out.

They disagree mainly on three things: what keeps long-lasting symptoms going, whether laboratory tests can help, and whether avoidance helps or harms.

What should I do if I suspect my home or workplace?

Who do I report the building to?

• Workplace or school: report it to your employer, for example your supervisor or the occupational safety representative. Occupational health care assesses what the building’s conditions mean for employees’ health, ideally together with a workplace indoor-air group (sisäilmastoryhmä). The decision on using the premises belongs to the employer [1, 11].
• Home: contact the property manager or owner first. They are responsible for investigating and fixing the problem. If nothing happens, contact your municipality’s environmental health service, the local health protection authority [12]. Under Finland’s Housing Health Decree, unrepaired moisture damage and microbial growth that residents can be exposed to exceed the action limit [1, 13]. The action limit is the level at which the decree calls for measures. Read more in our guide to water damage.

What if I also suspect CIRS?

The CIRS work-up includes an exposure history, the VCS test and blood tests such as MSH, MMP-9, TGF-β1 and C4a. These tests are not part of the Finnish recommendation. So you are likely to need a doctor familiar with CIRS. Our Finnish site keeps a list of CIRS-literate doctors in Finland (in Finnish).

A failed VCS test is a reason to investigate further, not a diagnosis.

For the symptoms people most often link to damp buildings, see water damage symptoms. For a comparison with another illness that causes fatigue and brain fog, see CIRS vs ME/CFS.

How strong is the evidence?

• Well studied Moisture damage and the airways. Independent reviews support the link between damp, mouldy buildings and respiratory symptoms and asthma [14]. Even here the picture is not simple. A 2025 Finnish follow-up of 30,418 school students found no link between inspection-confirmed mould damage in schools and new asthma [15].
• Environmental sensitivity as a functional disorder. Finnish and Swedish population and clinical studies support this view [9, 10]. So does a review of possible mechanisms, such as neurogenic inflammation (inflammation started by nerves) and sensitisation [16]. These studies did not find a toxic explanation. But they cannot prove that no biological cause exists. The recommendation itself says reliable biomarkers (measurable signs in the body) are lacking [1].
• Preliminary research Treatments for long-lasting indoor-air symptoms. The evidence is limited on all sides. A Finnish randomised trial tested cognitive behavioural therapy and psychoeducation (information about how symptoms arise). In a randomised trial, chance decides who gets which treatment. This one did not achieve a clear effect on its main outcome and was smaller than planned [17]. The recommendation calls for more research on rehabilitation [1].
• Preliminary research CIRS. The diagnostic criteria, tests and treatment protocol come almost entirely from Dr Shoemaker’s group and clinicians who use his methods [2, 4]. A 2024 review by CIRS clinicians found 13 published articles on CIRS treatment. Eleven of them were on the Shoemaker protocol [18]. Large independent trials are lacking. The Finnish findings that resemble CIRS come from small studies [7, 8].

The honest summary: both models describe real suffering, and neither has the final word. The first steps are the same. Fix the building, rule out other illnesses, and keep looking for help. You can read how this played out for the founder of this site in Joel’s CIRS story.

Remember these

Test yourself: Can you explain the main difference between the “functional” explanation and the CIRS explanation for symptoms that continue after leaving a building?

What next?

• Read what CIRS is.
• Read how CIRS is diagnosed.
• Read our guide to water damage.

References

1. Sisäilma ja terveys: potilaiden diagnosointi, hoito ja kuntoutus -työryhmä (Ministry of Social Affairs and Health). Sisäilmaan liittyvän oireilun ja sairastumisen hoitosuositus [Treatment recommendation for indoor-air-related symptoms and illness]. Terveysportti, Duodecim; 22 March 2024. Terveysportti
2. Shoemaker R, Johnson K, Jim L, et al. Diagnostic process for chronic inflammatory response syndrome (CIRS): a consensus statement report of the Consensus Committee of Surviving Mold. Internal Medicine Review. 2018;4(5):1–47. PDF
3. Finnish Medical Society Duodecim. Kosteus- ja homevaurioista oireileva potilas [The patient with symptoms from moisture and mould damage]. Current Care Guideline, 25 January 2017 (no longer maintained; archived version). Käypä hoito
4. Shoemaker RC, House DE. Sick building syndrome (SBS) and exposure to water-damaged buildings: time series study, clinical trial and mechanisms. Neurotoxicol Teratol. 2006;28(5):573–588. PubMed
5. Multiple chemical sensitivity: a 1999 consensus. Arch Environ Health. 1999;54(3):147–149. PubMed
6. Ministry of Social Affairs and Health. Lausuntoyhteenveto: Sisäilmaan liittyvän oireilun ja sairastumisen hoitosuositus [Summary of consultation responses]. VN/18878/2022-STM-36; 19 February 2024. PDF
7. Valtonen V. Clinical diagnosis of the dampness and mold hypersensitivity syndrome: review of the literature and suggested diagnostic criteria. Front Immunol. 2017;8:951. PubMed
8. Hyvönen S, Lohi J, Tuuminen T. Moist and mold exposure is associated with high prevalence of neurological symptoms and MCS in a Finnish hospital workers cohort. Saf Health Work. 2020;11(2):173–177. PubMed
9. Karvala K, Sainio M, Palmquist E, Claeson AS, Nyback MH, Nordin S. Building-related environmental intolerance and associated health in the general population. Int J Environ Res Public Health. 2018;15(9):2047. PubMed
10. Vuokko A, Karvala K, Suojalehto H, et al. Clinical characteristics of disability in patients with indoor air-related environmental intolerance. Saf Health Work. 2019;10(3):362–369. PubMed
11. Finnish Institute of Occupational Health. Sisäilma, terveys ja oireilu [Indoor air, health and symptoms]. Accessed 2 October 2026. ttl.fi
12. City of Helsinki. Asunnon terveyshaitan selvittäminen [Investigating a health hazard in your home]. Accessed 2 October 2026. hel.fi
13. Decree of the Ministry of Social Affairs and Health on health-related conditions of housing and other residential buildings and qualification requirements for third-party experts (545/2015). Finlex
14. Mendell MJ, Mirer AG, Cheung K, Tong M, Douwes J. Respiratory and allergic health effects of dampness, mold, and dampness-related agents: a review of the epidemiologic evidence. Environ Health Perspect. 2011;119(6):748–756. PubMed
15. Pekkanen J, Täubel M, Lehtimäki L, Marttila T, Karvonen AM. Inspection confirmed mold damage in schools and new use of drugs for airway obstruction: a cohort study. PLoS One. 2025;20(10):e0333486. PubMed
16. Nordin S. Mechanisms underlying nontoxic indoor air health problems: a review. Int J Hyg Environ Health. 2020;226:113489. PubMed
17. Selinheimo S, Vuokko A, Hublin C, et al. Psychosocial treatments for employees with non-specific and persistent physical symptoms associated with indoor air: a randomised controlled trial with a one-year follow-up. J Psychosom Res. 2020;131:109962. PubMed
18. Dooley M, Vukelic A, Jim L. Chronic inflammatory response syndrome: a review of the evidence of clinical efficacy of treatment. Ann Med Surg (Lond). 2024;86(12):7248–7254. PubMed

Please note: this article is for information only and does not replace a diagnosis or treatment from a doctor. If you have ongoing symptoms, contact a healthcare professional.