Radon levels: What do they mean?

Marie Bannister

Marie Bannister

November 1, 2021


Airthings most frequently asked question? "What do my radon levels mean?" Below we explain everything you need to know about your levels. Arm yourself with the information you need to make small changes to your home and improve your radon levels!



What are my radon levels, and what do they mean?

Measuring radon levels in a home or building is key to protecting the health of anyone breathing the air, but interpreting those levels is not quite as exact without a radon detector. As they say, everything is relative, and what is an acceptable radon level to one country or organization may differ from what is acceptable to another. This is influenced by numerous factors including the type of rocks and soil beneath a building, ventilation and duration of time spent in the building. 

One thing remains certain: radon can cause cancer. In fact, approximately 21,000 people die from radon-related lung cancer every year in the United States and  20,000 in the EU1. That alone should be the reason to find out if you, or your family, is being exposed to excessive levels of the dangerous gas.  Radon levels in the home need to be monitored daily as the levels fluctuate over time. Luckily, radon detectors can now monitor continuously and alert you to high levels, giving you peace of mind.

The World Health Organization recommends that countries adopt reference levels of the gas of 100 Bq/m3 (Becquerel per cubic meter). If this level cannot be implemented under the prevailing country-specific conditions, WHO recommends that the reference level should not exceed 300 Bq/m3.

7.1 million homes, radon

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Radon level measurement units

Radon is generated by the radioactive decay of radium, an element which was originally discovered in 1898 by Pierre Curie, Marie Skłodowska Curie and G. Bemont2. Radioactive elements are unstable, always in a constant struggle, deciding whether to hold onto all of their atomic energy in the nucleus or release some of it. That "decay" of the nucleus releases radiation.

Airthings Radon curie picture

One curie is equal to the radioactivity of one gram of radium, which decays at 2.2 trillion disintegrations per minute3. Sounds fast, doesn't it? It also sounds small, right? Read on.

Picocuries per liter of air, or pCi/L, which is one of the preferred measurements for the speed of decay in radon, is equal to one trillionth of a curie, abbreviated as pCi. The pCi unit is used in the United States because it is required by federal law. Just about everywhere else that uses the metric system, including the World Health Organization, measures in Becquerels. 1 pCi/L is equal to 37 Bq/m3.

Airthings radon Becquerel picture

The Becquerel unit, abbreviated Bq, is named after founder Henri Becquerel. The preferred radon level measurement unit is Becquerels per cubic meter, Bq/m3. One Becquerel equals one radioactive disintegration per second.

Safe radon levels

The best radon level measurement would be zero. Unfortunately, that's not possible. The average global outdoor radon level varies between 5-15 Bq/m3, equal to 0.135-0.405 pCi/L. For every 99.9 Bq/m3, or every 2.7 pCI/L increase in long term radon exposure, lung cancer risk rises 16%4. The thing to remember is that the lower the level, the lower the risk. As radon gas can accumulate indoors, it is important to monitor daily. Airthings radon detectors can give you peace of mind, so that you are notified when high radon levels occur. 




Airthings is on a mission to ensure people around the world take control of their air quality through simple, sustainable and accessible technology solutions; making radon and air quality solutions an essential and universal element for every building or home. That is why radonmap.com was created. The free tool can be populated with a huge amount of sensors from around the world, available to everyone. 

It is free to use, updated daily, and has thousands of anonymized radon sensors from around the world.  You can see yearly, monthly and approximate risk calculations in this easy-to-use, interactive map. 

Seasonality, ventilation, structural changes and location all make a difference to radon levels, which result in you having different readings to your neighbors. The best way to know the air you are breathing is clean and safe is by monitoring long term, with a detector that will track changes so you don't have to think about it!  Radonmap-4K-Screenshot

See nearby radon levels in your area at radonmap.com→

Healthy radon levels

A concrete answer to ‘what are healthy radon levels’ is highly disputable. Zero would be the natural answer, except that radon is a naturally occurring, radioactive gas that is in the air all around us. It is unavoidable, and in high levels over long periods of time can be dangerous. Hence the need for a radon detector, as its colorless, odorless and invisible, only through monitoring will you be aware of the levels in the air. 

Depending on the country, acceptable radon levels vary. A generally accepted action level established by the World Health Organization, the WHO, is 100 Bq/m3, or 2.7 pCi/L. Homes or structures measuring higher are advised to take remedial action to lower radon levels. The WHO further advises an upper limit that should not be exceeded at 300 Bq/m3, or 8 pCi/L.

In the United States, the Environmental Protection Agency action level of 4 pCi/L is the standard, a little higher than that of the WHO. It is also thought that reducing levels to sub-4.0 p/Ci would cut yearly cancer deaths from radon in half.Ground-floors-and-basements-Inserts

Wave  Want to measure radon from your smartphone? Check out Airthings Wave Radon.

Radon level chart

Airthings View Plus,  Wave Radon and Wave Plus have a color-coded visual indicator. This makes it easy to get an overview of the air in your home. In addition, you can check in the Airthings app if the radon sensor is good (green), fair (amber)  or poor (red). Radon level chart

Wave  Want to measure radon from your smartphone? Check out Airthings Wave Radon.

A simple solution

High radon levels can be fixed easily and simply. Whether it is following easy radon reduction tips, increasing ventilation, performing DIY fixes or contacting a radon mitigator, radon gas levels can be improved dramatically. The first step is to monitor, so that you can be alerted to high levels and make small changes where necessary.  



Airthings Wave Radon - Hero Image - Main with Simplified App_GLOW_WEB_Transparent

This is Wave Radon

A smart radon detector with quick and accurate results on your smartphone. Additionally, you can simply wave in front of the device to get a visual indication of your radon levels.

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1. https://www.epa.gov/radon/health-risk-radon






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Thousands of Radon sensors across the world, broken down by location. See your region's approximate risk level.


Thousands of Radon sensors across the world, broken down by location. See your region's approximate risk level.