[sizzle]

I always crack my sunroof an inch and pull the shade forward go get some fresh air in recirculate mode so I’m not picking up crap from the engine bay.

How does the fresh air mode on the car not pull in CO gases from the engine bay? Surely a pleated cabin filter is not enough to stop it? Or does the air come from the manifold air intake?

[bruckie]

There should be very low levels of CO (at least from your car) in the engine bay, since exhaust is vented out the back of the car, and your engine shouldn't be leaking exhaust gases in other places. You might have some CO there from the cars in front of you, though.

[lukevp]

The air intake in the grille is only for the engine’s use. The fresh air intake is not in the engine bay, it’s typically at the base of the windshield.