Acceptable levels according to your location
The information below is taken from governmental agencies and official national organizations that regulate radon and air quality. Most of the measures were taken in periods of one year or more.
While most of the countries stick to values suggested by international organizations, like the WHO, each country makes exceptions based on local soil conditions and other industry regulations.
Most countries set different action levels for homes and offices, the latter being higher than residential ones. The links provided here contain information about action levels for homes; some of them also include workplace information.
Although the effects of radon were first documented as early as 1530 in Europe, the famous “Watras incident” in the U.S in 1984 put radiation regulations on the map. Since then many studies have been carried out to find a correlation between lung cancer and radon exposure.
That’s why recommended values in North America are lower than those recommended by the WHO, and workplace regulations –especially regarding power plant and mine workers– are stricter and more comprehensive than in Europe.
Recommended levels in Canada are set at 200 Bq/m3. Any buildings with higher levels require mitigating actions and, for spaces with levels higher than 600 Bq/m3, these actions must be taken within a year.
If the levels are between 200 Bq/m3 and 600 Bq/m3, mitigation has to happen in less than two years. The Canadian government states that these levels are “based upon current scientific understanding”.
You can visit the radon section of Health Canada’s website to learn more about specific radon regulations and get access to resources that the government of Canada has created for the general public.
The U.S. Environmental Protection Agency (EPA) is the one in charge, among other things, of creating radon laws and regulations. The agency has done a good job at spreading awareness about radon and providing information to the general public.
According to the EPA’s “Home Buyer’s and Seller’s Guide to Radon”, almost one in 15 homes in the U.S.A. has radon concentrations above the recommended levels. This guide includes a lot of useful information about radon; you can read it here.
They have created a very useful chart that compares the risks of smokers vs. non-smokers with the likelihood of getting lung cancer. You can see it here. Acceptable levels in this country are between 2 and 4 pCi/L.
The European Environment and Health Information System (ENHIS) has surveyed 13 countries in Europe and recommends action levels between 200 Bq/m3 and 400 Bq/m3. There are specific guidelines for each country since the type of soil varies both per country and within each region.
ENHIS states in its 2009 report, which you can read here, that “there are clearly huge differences between countries in terms of exposure to radon in dwellings in Europe”. That is why it is important to pay attention to local concentration levels and that way you can also learn if you live in an area that is considered a “risk zone”.
Germany, Poland, the Netherlands and the UK will have lower levels, in average, than Austria, Finland, Sweden or Czechia. However, the downside of using geographical expectations is that if your home is built over sedimentary soils, radon can over-concentrate if ventilation is poor. If you live in a high-risk zone you can have low levels in your home, if you live in a low-risk zone you can have high levels in your home. This is why every single home needs to be tested.
According to the Norwegian Radiation Protection Authority, “Norway is among the countries in the world where indoor radon reaches its highest concentrations”. About 10% of all buildings in Norway have a concentration higher than the recommended 100 Bq/m3.
Current legislations set the limit at 200 Bq/m3 for schools, new buildings, and rented accommodation. The action level for reduction is set at 100 Bq/m3, in accordance with WHO’s recommendations.
The government has discussed targets to reduce and control radon in Norway; existing buildings in the country “with indoor radon concentrations exceeding 200 Bq/m3 must be considerably reduced by 2020”. For more specific measures and procedures, you can check the official guide here.
Because of the type of soil, most homes in France have an average indoor concentration of 90 Bq/m3. Even so, there are about 300,000 buildings with concentrations over 400 Bq/m3 and about 60,000 with levels higher than 1000 Bq/m3.
Regions that are rich in granite, like Bretagne and Massif-Central, have the highest concentrations in the country. You can consult France’s radon map here. New buildings are expected to have levels of 200 Bq/m3 and below. However, because of the type of soil, the government only recommends taking corrective actions for levels higher than 400 Bq/m3.
According to radon mapping in Germany, between 10% and 50% of buildings in the country have radon levels over 100 Bq/m3, for which actions are required. If levels are above 1000 Bq/m3, mitigation has to be implemented within a period of three years.
All new buildings are expected to have concentrations below 100 Bq/m3. The Federal Office for Radiation Protection recommends ventilating frequently and intensively and sealing cellar doors and cracks or gaps in areas that are in direct contact with the soil.
The agency for Environmental Quality in Italian Urban Areas states that more than 10% of all cases of lung cancer in Italy are related to radon. The country follows its own guidelines, as well as those of the European Union, and there are public and private companies that help people measure their indoor air quality.
The radon regulations of the government of Italy include only schools and offices, where radon levels need to be reduced if they are above 500 Bq/m3. Households are excluded therefore homeowners are solely responsible for measuring indoor radon levels.
According to the Council for Nuclear Safety of Spain, laws regarding exposure to radon were re-established in 2006. The government of Spain recommends following EU guidelines and introducing corrective measures for concentrations above 400 Bq/m3 in existing buildings.
Laws previous to 1993 required actions at 600 Bq/m3. After Spain became part of the EU action levels were changed to follow WHO’s recommended levels and EU guidelines. The official report is available here, in Spanish.
The project to create a comprehensive radon map of Spain was finished in 2013, and it is available here. The goal of this project was identifying zones and regions that were most likely to have high concentrations of radon to reduce exposure as much as possible.
According to the Swiss Confederation's Federal Office of Public Health, the guideline for radon indoors in new and existing buildings is 400 Bq/m3, with a limit of 1,000 Bq/m3. These guidelines are to be reviewed in the Autumn of 2021.
The Department of Public Health England has created a very useful interactive radon map where you can see specific concentrations in each area of the UK. Take a look at the map here.
As of 2010, the UK's Health Protection Agency set 100 Bq/m3 as a target level “because research published since 1990 has given scientists a greater understanding of the risks to our health of exposure to radon below 200 Bq/m3”.
Actions are recommended for levels above of 200 Bq/m3. You can find a pricing list to know the costs of active mitigation methods, should your levels be too high. You can consult them here.
Hopefully, your radon levels will be within the recommended values. Don’t forget to keep ventilating and, once again, thank you for purchasing an Airthings detector.