[HansR]

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.

Yes, you may be right but AQI is derived from the actual concentrations and therefore - if devices are compared - devices should give - roughly at least - the same concentrations.
We need not discuss it here in depth, it is now clear to me what you are doing in the code, that's important.
If I have any other remarks in this I will PM you.

Regards,
Hans