How to clear up the stink?

Here is the dilemma. I live in a small room with my roommate and unfortunately he does not shower too often and he wears the same dirty clothes repeatedly. I have told him this and he doesn't do anything. I even offered to clean his laundry, but no. So there is a definite odor when you walk into the room. Right now, I have a glade plug in running at 5. What else can I do? I cannot open the window due to it being winter time. Any suggestions?