@llewelly @dinogami @helenczerski I own a pest control business, and one of the things I have picked up over the years is that some museums use CO2 as a low-impact form of pest control. Usually the items in the collection are put into a special unit for the treatment, but it wouldn't surprise me if some of the gas escaped, and thus raised the level in the rest of the museum. I don't know how much it would take to be detectable. https://museumpests.net/conferences/museumpests-2014-conference/museumpests-2014-treatment-remediation/
@Ambulocetus @llewelly @helenczerski This is fascinating! I had no idea about this--as a paleontologist working primarily in fossil-based collections, pests weren't really a worry, but I can definitely see it needed for specimens of modern animals (I know dermestids are a serious concern for taxidermied specimens). I never really learned anything about what kinds of pest-control measures museums have to take to ward off such pests, but I guess spraying chemicals around isn't really a great idea.