It has to be under 40dB on max. People say, "Oh, it's fine, I'll turn it down," but that doesn't happen; it gets left off.
But if you try to sell a 40dB purifier, the CADR is lower than the unusable louder model, and no one wants it.
So they get the loud one, and it either gets turned off or set to a lower power that actually offers less CADR for the noise level than the model with the fans purpose-built to run quiet all the time.
it’s so fucking outrageous how common it is for medical facilities to have their air purifiers not in use—so often i have to turn on or first plug in these long-abandoned tools for cleaning the air. this timeline is committed to misery.