It looks like an Asian Brown Flycatcher to me.
I don't think a lack of air would be a problem - there should be plenty of air in an office for a small bird such as this.
The bigger problem is likely to be food. the bird will need to eat regularly, especially in the recent cold weather. Sadly, even in the wild an insect-eating bird like this may not find enough food to survive this cold weather - this is one reason that many species migrate south.
I hope it was able to get out of the office yesterday to look for more food. I agree with Dave that the best idea in a situation like this is to open a window and try to get the bird to fly out on it's own
