When air comes out of your nose and mouth suddenly. What is it?

This is my favorite place in school because I love science. We have to wash our hands when we leave this room. I’m in the _______________ .

After lunch, I usually go to the ___________ to use the internet. On other days, I go to the courtyard and talk with friends. Sometimes, we even play games together here.

Something that causes disease and illness. What is it?