[werk_ag]

... very difficult to say something about it and measure the correctness of the output. Comparison becomes difficult.

Perhaps it's not a direct comment on your thought which I think I have understood.

I believe the main purpose of any Air Quality device is provide an AQ Index (whatever the standard), which usually is a rolling average over a time period. Thus, what eventually makes sense, when comparing different AQ devices, is comparing the resulting AQ Index for the same time period, and not the instant output of each one (hardly two of them will have the same output at a given moment). Just a thought.