[FletchLives]

the roommates are obviously disrespectful, were they like that at the beginning? did D used to smoke?
"they just sort of blow it off" is a cop out. people can only disregard you if you let them. so what exactly did you tell the roommates D?
is the 2nd roommate also paying rent? who's name is on the lease?

honestly D, my guess is that you have been way too passive. you probably let this boil up inside and only made some passing comments about it bothering you.
quit being a little bitch, sit your roommates down and tell them what's up. if you had already done this, you wouldn't be asking for advice on here.
(but this is a guess)