Why Clean Air Matters

I live in a pretty cheap apartment near campus. It doesn’t have any bells and whistles, but I’m fine with that. There is one thing that concerns me a little bit, though, and that’s the fact that there is mold around and the air kind of smells… funny. It makes me worried that I’m breathing “unhealthy air,” or something. It doesn’t help that my roommate is a smoker, though he likes to think that the cigarette smell overpowers the moldy smell (thanks, I guess!). How concerned should I be about the air I’m breathing when I’m at home? I’m only there at night and a few hours during the day, and only when school is in session, if that matters.