English is my first language and FTA your coal pollution hypothesis would seem to be refutednwhich I think was what they were pointing out because so few people DO read the article... E.g. more species would seem to be affected although perhaps it's a compound effect such as the pollution weakens some species more and some bacteria/virus/etc. kills them in their weakened state. I do appreciate your contribution about the local pollution sources.

I was born and raised in the US.

"Has to think" is not a common construction, if you're trying to communicate something across the lines of "can't help but think".