Question

If someone sitting at the other end of a restaurant smokes a cigarette, you may still breathe some air in what is that called

Answer 1

I believe what you are talking about is second hand smoking, but this mostly applies to small closed in spaces.

Is this what you meant?

Answer 2

Not sure if this is the answer you are looking for, but if you breathe in cigarette smoke but you yourself are not smoking, that is called secondary smoke inhalation or secondary smoking