Is it illegal to sleep in your car?

I have no where to stay for the night im in college for summer school and i have a midterm tmrw. after its fine its just this one night. my options are sleeping in the library or in my car and thats really it for this one night. I live in a very safe college town. if i crack my windows a bit can i breath? my main concern is i plan on parking on in my old apt parking lot but a private security car comes through there at night but they dont really check nside cars and stuff. will i be arrested for doing this? i cant afford that because i have a midterm tmrw