That's very interesting, Bill.
I’m sure that monitoring would be relatively simple but that those with financial interests would much prefer not to see the results. Filters are also relatively cheaply available.That's very interesting, Bill.
It's not my field so I don't recognise the instruments that the passengers are using, but three of the four videos uploaded to the site you have provided a link to show the air quality as and the background radiation as high - in fact dangerously high on one instrument. I'm aware that background radiation increases with increasing altitude simply because there's fewer air molecules to absorb interstellar radiation. Unfortunately the videos aren't of sufficient quality to read the measurements clearly. Three of the videos show the same type of instruments being used and the fourth video a single, different air quality monitor.
I assume the users have had the instruments calibrated to some kind of recognised standard.
If it's this easy to measure air quality, then surely it's built into the instrument suite of a modern aircraft's monitoring system?
And if not, why not?
Thank you for posting the extra information.
I. for one, would appreciate you updating this thread occasionally.