[imp0cat]

I am aware of a recent youtube video where some guy measured the CO2 ppm scores with recirculation on. The results are (obviously) quite terrible after a while.

But I don't think car manufacturers care about that. I think the switch to fresh air after a while is mainly to prevent the windshield from fogging up.

[cptskippy]

Which is also absurd because other automakers have other less annoying options. I had Hondas that just vented outside air just to the defroster vents without disabling the re-circulator. The Tesla Model 3 can send heated or AC chilled air to the defroster by tapping the defroster button to cycle options.