OT: Something in this house is making me sick

Someone posted something here about cleaning window a/c's with borax or something when they had a bad cough, and I can't find the post.

I have been coughing like mad for weeks. Not a cold, no fever, no congestion, just this horrible hacking cough. I went on a trip out of town and did not cough once. Came back, walked into the house and started coughing.

We have Central a/c, but I also have a window a/c in my room. I cleaned the filter, then went out and found that the house a/c filter had not been changed in months (not my job). My roommate/house owner is the laziest person I've ever seen. She has also been sick for the last month with cold/flu-like symptoms, so I'm sure that had something to do with it.

I cleaned the dust off of all the ceiling fans (mine was fine, but the rest of the house was horrible -- some even had cobwebs, they hadn't been cleaned in so long).

I am still coughing. I don't know what else to do. My roommate won't let me turn the a/c up over 84 during the day, so there is really no "air cleaning" going on. Plus, about a month ago, she had them put some kind of chemical into the ducts to seal leaks and disinfect them. I'm wondering if that doesn't have something to do with it.

I can literally SEE the dust in the air, and I'm sure there are mold spores in there too.

I'm going to start taking my garlic, Iodine and borax again to see if that helps kill whatever this is, but I think it's in the air. Any suggestions? I'm cleaning everything really well, spraying super-saturated borax on every surface.