Is workplace radon measurement mandatory in Finland?

Yes, in defined cases. Under the Radiation Act (859/2018, Section 155), employers must measure radon in workspaces that are underground, on air-permeable soil, or on the ground floor in STUK-designated measurement-obligation areas.

Can an air purifier reduce radon?

No. Radon is a noble gas; HEPA and carbon filtration target particulates and VOCs, not radon. Radon is controlled by ventilation and structural mitigation.

What is the radon reference level for Finnish workplaces?

300 becquerels per cubic metre (Bq/m³) as an annual average for regular work over 600 hours per year.

What is the most common source of poor indoor air at home?

Cooking. Frying and high-heat cooking can briefly raise fine-particle (PM2.5) levels sharply; extraction and ventilation are the main fixes.

What does carbon dioxide (CO2) indicate indoors?

CO2 is a reliable marker of under-ventilation. Raised indoor levels also track measurably weaker cognitive performance.

Is damp or mould a real health risk?

Yes. Occupants of damp or mouldy buildings carry substantially higher risk of respiratory symptoms and asthma.

FAQ

Questions about radon and indoor air

Straight, sourced answers on the law, the science, and what we actually do - for radon compliance and everyday indoor air quality. Every claim links to a primary source.

Radon & compliance

Is workplace radon measurement mandatory in Finland?: Yes, in defined cases. Under the Radiation Act (859/2018, §155) employers must measure radon in workspaces that are underground, on air-permeable soil, or on the ground floor in STUK-designated obligation areas.^{[5] , [7]}
Who is responsible - the tenant or the landlord?: The duty to measure occupational exposure falls on the employer occupying the space, even in rented premises.^[7] The owner handles the building's structure under separate rules.
Can an air purifier fix a radon problem?: No. Radon is a noble gas; HEPA and carbon filtration target particulates and VOCs, not radon. Radon is controlled by ventilation and structural mitigation.^[4] We're upfront about that distinction.
What if we exceed 300 Bq/m³?: Often a one-week working-hour measurement shows real exposure during operating hours is compliant, because ventilation runs during the day. Roughly half of such sites clear without remediation.^[6]
Why is radon measured only from September to May?: Radon is drawn indoors most strongly in winter, when buildings are heated and sealed, so the official measurement season runs 1 September to 31 May, with detectors in place for at least two months.^[5]
How do we actually know radon causes lung cancer?: Radon is an IARC Group 1 human carcinogen, and a pooled analysis of 13 European studies found lung-cancer risk rising measurably with exposure, with no safe threshold.^{[3] , [9]}

Indoor air quality

Can an air purifier actually improve my air?: Yes, for what it's designed to do: HEPA removes airborne particulates and activated carbon adsorbs many gases and odours, measured against guidance like the WHO annual PM2.5 level of 5 µg/m³.^[8] It just can't touch radon.
What's usually the biggest source of bad air at home?: Cooking. Frying and high-heat cooking can briefly push fine-particle levels past a busy roadside; extraction and ventilation are the main fixes.^[8]
What does CO₂ tell me about a room?: CO₂ is the cheapest honest marker of under-ventilation, and raised levels track measurably weaker cognitive performance.^[10]
Is damp or mould really a health issue?: Yes. Occupants of damp or mouldy buildings carry substantially higher risk of respiratory symptoms and asthma, and it's measurable.^[12]
Are formaldehyde and VOCs dangerous?: Most VOCs are harmless at indoor levels, but a couple - formaldehyde and benzene - are classified as carcinogenic to humans, so ventilation after a renovation matters.^[11]

References

Still not sure where you stand?

Check your radon obligation in 30 seconds, or ask us about your indoor air.

Check your obligation