I don't normally get involved in subjects (146) that I have no knowledge of, but I am going to ask of RD, who I know pretty well, and who is not at all dodgy, just a couple of points.
1. IF....there is a known problem - or not known - but occurrences have caused cabin air problems. What was the cause and the resolve?
2. IF....someone says "oh it must be APU air!" what can be done about that?
3. IF....there is a fault that causes the system to suck in foul air, from apparently different scources, what can or has been done about it?
In all my years in flying I have known many cases of the cabin becoming a bit iffy but it was never anything serious. Is that the case here RD?
Interesting subject though.....but not as serious as some would have us believe I think!