There have been too many well documented instances of tests, victims and investigations for it to be challenged realistically
Let's be honest: There haven't. Lots of people posit that cabin air is affecting health but, thus far, there's been nowhere near enough robust evidence to prove this. Quite a lot of scientists have written papers about this, so far none of them have come to a robust conclusion.
With more research and more data that will change, but basing things on individual cases, anecdotes and the borders of conspiracy theories is not the way to move forward. That just detracts from the argument.
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2017 Aircraft Cabin Air Quality Conference
This is the type of thing we need more of. Bringing experts (and Jim Lovell
) together to discuss it properly.