[quote=Mortalbean]
Actually with two on east coast and one in the Midwest it makes sense that the US could have 5, the other countries(like Russia) have their populations more heavily focused in one area.Also, could you just say that all the pollutants caused poisonous gas clouds to form which engulfed the earth(because there is a delay between when pollutants are released and when they reach the "upper" atmosphere.
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I was likely going to just use mutated algae and a different fictional gas as suggested by someone else, but I think I'll definitely incorporate that idea. Now that my panic attack is over it should be up relatively soon, because I won't be spasming over rewrites.

EDIT: And also, thanks. I'm not an expert on how the global population is dispersed, so that helps a lot!