“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 order to calculate the actual radon concentration, there is quite a lot of math involved. A new calculation is run every hour and involves the counts for the past 24 hours. So every hour there is a new update to a 24-hours average.

In practical terms, this means that if you had an abrupt change of radon concentration from - say - zero to 1000 (and held it there), the expected reading would be a rising concentration level over 24 hours until it reaches the new steady state. The 30 minutes of diffusion time in the sensor is negligible in this scenario.

It is important to note: the statistical nature of the detection of the alpha decay adds a random component to the radon count, and the way the app presents the data. This introduces another level of averaging depending on the time window the user is looking at in the plots.

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