Test your home for radon
Testing can reveal an invisible lung cancer risk that a qualified installer can reduce.
The number, drawn
Why it matters
Radon is a radioactive gas that can enter buildings from the ground. WHO estimates lung cancer risk rises about 16% for each 100 Bq/m3 increase in long term average radon concentration. Testing identifies exposure; any benefit depends on reducing a high result, and risk is greater in people who smoke.
How to do it
- Ask your local radiation or public health authority about approved home testing.
- Use a test kit or qualified tester according to local instructions; longer measurements better reflect average exposure.
- Compare the result with your national action level; WHO advises a national reference level no higher than 300 Bq/m3, and arrange professional mitigation if yours is elevated.
- Retest after mitigation to confirm the system is working.
Action levels vary by country and do not mark a completely safe threshold. Use a qualified radon professional to interpret high results and plan mitigation.
Do it
Pick the time you have. Anything beats nothing.
Start with the time you have
5 minutes
Find your local radiation or public health authority's radon testing advice and check how to obtain an approved kit or qualified tester.
15 minutes
Compare the recommended testing options and request a suitable kit or tester; check the measurement period and how results will be returned.
A plan
Test, interpret and reduce exposure
- Ask your local authority about approved tests, duration and national action levels.
- Place the kit exactly as instructed and leave it for the full measurement period.
- Send it for analysis and review the result using local guidance.
- If elevated, arrange qualified advice on confirmation or mitigation, then retest after the work.
In real life
- Before turning a basement into a bedroom, ask your local radon authority about testing it.
- After professional radon reduction work, arrange a repeat test to check the result.
Watch out for
- Common mistakeRadon has no warning smell, so use a test rather than judging the air yourself.
- Common mistakeA quick test does not represent every season equally, so ask which testing duration fits your situation.
Trusted guides
In Spain
In Spain, Royal Decree 1029/2022 sets a reference level of 300 Bq/m3 for the annual average radon concentration, a value recommended not to be exceeded rather than a legal limit. Radon maps are only a guide and do not replace direct measurement in your home.
Check usSources
- Evidence grade
- B Consistent large cohort studies, with some trial evidence.
- Basis
- WHO synthesis of residential radon studies and CDC testing and mitigation guidance
- The number
- About 16% higher lung cancer risk per 100 Bq/m3 of long term radon exposure (WHO, 2023)
- Outcome
- lung cancer risk with higher long term radon exposure
- Comparison
- Per 100 Bq/m3 increase; an exposure association, not a testing benefit
- Tier 1 guidelineRadonWHO, 2023
- Tier 1 guidelineTesting Your Home for RadonCDC, 2026
General health information, not a diagnosis or an individual treatment plan. Personalization changes the order of suggestions; it does not assess your medical risks. Follow the cautions and consult a qualified clinician when needed.