Radon in Europe: national means span 20 to 140 Bq/m³

Key takeaways

• Published national means span 20 Bq/m³ in the UK to 140 in Czechia, a factor of seven, from surveys that, where dated, fall between the 1980s and 2007-08.
• The JRC map puts the mean of its 10 km cells at 98 Bq/m³, from about 1.2 million dwellings in 32 countries.
• All 13 national reference levels sit at or below the EU ceiling of 300 Bq/m³: eight at 300, three at 200 and two at 100.
• A reference level triggers action in existing homes and is not itself a limit in most of these countries, and every national mean is below its level.

Czechia reports a national mean of 140 Bq/m³ for indoor radon. The UK reports 20. Yet the level at which a Czech owner is expected to act is 300, and the UK’s is 200. We read the national mean and the reference level from the radiation-protection authorities of 13 countries and set them against the EU ceiling of 300 Bq/m³.

Why this is not a country map

The European Atlas of Natural Radiation, run by the Joint Research Centre (JRC), publishes an indoor radon map under CC BY 4.0, so the picture can be reused with credit. The numbers behind it cannot. The JRC states that the measurements and the grid-cell statistics belong to the national data providers, and it does not share them. So we use figures the national authorities publish themselves.

The map shows arithmetic means over 10 km cells of ground-floor rooms. A 2019 paper in Natural Hazards and Earth System Sciences, which sets out the method, reports a mean of 98 Bq/m³ across the map, built from almost 1.2 million dwellings in 32 countries with data to the end of 2018. The paper cautions that the map is not representative of the radon exposure of European citizens and says nothing about a particular building.

National means and reference levels

Bq/m³ is becquerels per cubic metre of air, one nuclear decay per second in each cubic metre. Our radiation units converter covers the becquerel and its neighbours.

What the numbers show

The ceiling is set by Directive 2013/59/Euratom. Article 74 requires each Member State to set national reference levels that do not exceed 300 Bq/m³ as an annual average. Eight of our countries sit exactly there: Finland, France, Italy, Germany, Czechia, Austria, Spain and Switzerland. Sweden, Ireland and the UK set 200. Denmark and Norway set 100. Finland and Italy keep 200 for new homes.

The surveys differ in age. The UK’s 20 comes from a survey of over 2,000 homes in the 1980s, and the UK government’s draft national radon action plan says it may now be out of date. Czechia’s 140 is undated on its source page. Germany’s authority gives about 65 and also estimates that almost 2 million people live above 300.

A reference level is not a ban. Germany’s authority says plainly that a reference value is not a limit value. It describes it as a benchmark for judging protective measures, which can make sense below it too. A level of 200 or 300 sits well above every mean here because it aims at homes far above the average.

Limits

The means are not comparable like for like. They differ in survey year, weighting and housing type, and several pages give no basis at all. Austria, Spain and Switzerland publish a level but no national mean in the pages we read.

We left out four countries. Belgium’s agency pages blocked automated reading, so we could not verify them. Poland gives a level but no mean. The Netherlands gives 23 for its whole housing stock and 30 for new homes of 1985 to 1993, and no level on the page. Iceland has a mean of 5 to 13 Bq/m³ and no reference level. Switzerland, the UK and Norway are not EU members, so the directive does not bind them. A national mean says little about one building, so measure your own home.

Cite this: ScienceShot, Radon in Europe, November 2026, scienceshot.com, scienceshot.com/post/radon-in-europe-national-mean-indoor-levels.

Sources: Nordic Radiation and Nuclear Safety Series 01:2024 (Nordic-Nat, for Denmark, Finland, Norway and Sweden); ASNR; ISIN; BfS; EPA Ireland; SÚRO and SÚJB (Czechia); UK Government draft national radon action plan and UKHSA; AGES; CSN; BAG; JRC REMON European Indoor Radon Map 2024; Elío et al., Nat. Hazards Earth Syst. Sci. 19, 2451 (2019); Directive 2013/59/Euratom, art. 74. Retrieved 30 Oct 2026.