You can see fluctuations in radon levels due to 2 main reasons:
- The nature of radon itself
- The way radon is measured
1. The nature of radon
Radon is an invisible gas formed in the Earth’s crust. It surrounds every one of us as part of the air we breathe. Radon gas is the result of the breakdown of uranium in the Earth and then rises from the ground as a gas and enters our homes.
The amount of Radon emitted from the ground and the amount that actually enters our home can change due to the following reasons:
- Building insulation
- Building foundation
- Use of water
As radon is prone to such fluctuation, it is important to measure radon long-term, so you stay on top of any changes which occur.
2. The way radon is measured
The radon sensor in all of our products is made by Airthings. It uses "alpha spectrometry" to measure the level of radon it was designed by our in-house CERN scientists. 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.
Radon is a gas, so the amount of alpha radon particles in one particular sample can vary dramatically from one air sample to the next. Radon will not be distributed evenly around a room. This is why we recommend allowing your monitor to measure for at least 30 days, so that the monitor can obtain enough air samples to provide a reliable long-term average.
We have a useful analogy to explain how our radon sensor sampling works, by using your everyday cup coffee!☕
Radon is NOT always evenly distributed throughout a space. Imagine a cup of black coffee to which you add a dash of cream but DON’T stir. If you then take multiple samples from a small spot of that coffee for level of cream, you would get wildly different answers over time as the cream slowly blends with the coffee. That’s why our sensors give a sample (short-term) reading AND an average (long term) reading. Radon levels can vary widely throughout the day, week, and even location within the space.
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