Didn't Rome still use the "eat, shit, and sleep on your seat" system used by the Greeks before them? I don't think rowers had anything that could reasonably be described as "fresh" air.
I think compared to deep mining shafts, before proper ventilation and smokefree lighting was invented - it definitely can be described as fresh air in comparison, however disgusting the rows were - on the sea is always wind blowing most of it away. But of course it mattered, whether you were on the top row or the lower rows - and where you would sit was also used as further punishment/reward.
