Radon, emitted naturally from uranium decay in the soil, can enter buildings and, over time, pose a serious health risk. Prolonged exposure to elevated radon levels is linked to lung cancer, making it crucial to monitor and mitigate this gas, especially in residential and office spaces.

The Space Plus is the Airthings device used to measure radon. The radon sensor consists of a passive diffusion chamber, which allows air samples to flow into it. There is a photo diode located inside this chamber, which essentially counts the amount of "daughter" radon particles in the air sample.

“New” air fills the passive diffusion chamber sensor in about 30-45 minutes. The sensor itself (photo diode inside) counts events continuously, and it keeps a ledger of these counts on an hourly basis.

In the Airthings Dashboard you see a graph that represents the hourly radon values. The device does a radon count every hour and it is that raw data that is shown in the graph. Radon moves through the air, so when you in general have low radon values, it can happen that there sometimes is a high radon count. This would be when the sensor samples the radon value, just at a moment when there is a higher amount of radon in the air around the sensor. When you have high values over long time, this is not a combination of circumstances anymore and the data is representative.

The radon report lets you take a look at the radon levels over a longer period. The report takes the measured values during the chosen period and shows the averages in a week. You will see:

Our sensor has been tested by independent labs around the world, and we obtain a Calibration Certification from the German Federal Office for Radiation Protection on an annual basis. Based on these tests, the accuracy/precision of our sensor is stated as the following:

Accuracy/precision after 30 days of continuous measuring:

This means that if you measure for 30 days continuously, and then check your "1 week average" figure for the last 7 days, the readings would be ~ ±10% of the actual radon level if the levels were approx. 200 Bq/m3 or 5.4 pCi/L. At this level, this means the monitor could show:

If you measure for longer, such as 2 months, and then view the average radon level for those 2 months, the level you see would be ~ ±5% of the actual radon level, if the levels are around 200 Bq/m3 or 5.4 pCi/L.

The reason the accuracy is stated at the particular level of 200 Bq/m3 or 5.4 pCi/L is due to the relation of accuracy and precision. If radon levels are lower, there is more of a chance that the deviation will be greater. If you allow the monitor to measure for longer, it will provide more accurate long-term readings, as it gains more data from the air samples obtained.