Dusty

Have finished dusting and vacuuming the bedroom. Holy crap, where does it all come from? Seriously!? I mean, there's stuff on the desk that I know for a fact has been there for five days, and it was covered in a layer of dust. Should you be able to accumulate offensibly visible dust in less than a week? Is it us - are we some kind of horrible dust-shedding mutants? Is it the window open? Is it the fan dug out of storage? Because this is disgusting!