@catsalad

I'd go for 99.9% on the grounds that that might actually be true.

Although the question reminds me of a chemistry class where we were asked to analyse the purity of a sample. And when I sheepishly admitted to a result of 102%, the teacher said "Good, it was analar grade [highly pure], and the method has an error margin of around 2%".

@catsalad more interested in the purrest

@catsalad idk, but this one time 99.9 and 100 got together, and it was totally a purecest

@catsalad 112%, if hollow knight taught me anything

@catsalad exempli non grata: would not trust 99.9% air purity with potential for over 1000 ppm CO₂