Actually yes ...
the fine particles in the air has a debilitating effect on the strings that will cause the metal core of the string to oxidise and thus causing it to lose it sustain and brightness ..
then again, all the above i just typed was made up and nonsensical .. hahahahah
no lah, i don't think putting your strings in the open will actually affect them. yes, we live in a moisture rich environment that has a humidity level of close to 90% ... that may affect the woods of the bass but for strings, highly unlikely that it'll die really fast,
strings after a while will set in, new strings will take around 2 weeks to set into it's actually playing state, from my experience .. after that the sustain will be affect by constant playing, e.g. dead skin from your hands, .. actually mostly dead skin .. hahahah .. it's pretty gross to think about it but that's true for all of us who play the bass very often.
i'm using DR strings now ... it has lasted me for 5 months and settled in very well, it still has that brightness even though you can tell it's pretty dead now but it plays very well, very even across the board.
i think i should methylated spirit my strings soon ...