I just walked around the library. I found that some areas are a bit cool but some are warm and stuffy. No parts seemed to be cold but I didn't sit for any period of time. Since you identified yourself as a graduate student, I did check out the FHS Graduate Student study room which was a pleasant temperature but noisy due to the air ventilation.
Unfortunately, the temperature in the library is controlled centrally and varies greatly between areas, times of day, day of the week and season of the year. However, if you could be a bit more specific about the area where you were sitting we could get engineering to investigate.
As for the coughing, runny noses and sneezing, sometimes I think we should rename ourselves as the Sick Sciences Library; however, we are not allowed to screen for infectious diseases before admission to our space. Evidence shows that you should wash your hands frequently and not put your hands anywhere near your face: http://www.webmd.com/cold-and-flu/cold-guide/cold-prevention-hand-washing
Answered by: Liz Bayley (Director, Health Sciences Library)