[RobotToaster]

Fun fact, the air quality on aeroplanes got worse after they banned smoking, because they could cut costs by re-circulating the same air for longer.

[7jjjjjjj]

Recirculated air is still a thousand times cleaner than air with cigarette smoke in it.

[IAmBroom]

You are naively assuming the only really dangerous part of recirculated air is nicotine byproducts.

Bacteria and virus loads are far more dangerous. Cigarettes take longer than a couple weeks to kill.