Does the cabin filter filter air coming into the cabin in the "fresh" mode or does it only work on the recirculation mode?

I like to drive with the fresh mode to let air come in, but with spring and pollen and my allergies, I was wondering if the fresh air mode with not affect my allergies.

Thanks.

 

I'm curious as well, does anyone know?

 

I find bugs and leaves in it, so I'm assuming it comes from outside since I don't have any trees or nests inside my car ;-P

I think it's supposed to filter all air, otherwise your system could get full of gunk (ie: even if it worked in recirculation mode, it might suck in dirt that already made its way inside previously).

 

The cabin filter works in "Fresh Mode", as I almost never use the recirculation mode and my filter gets pretty dirty.

 

Just a total SWAG, but the filter is positioned near (presumably ahead of) the blower motor. I imagine the valve that shutters between fresh/recirc is farther away, and so I'd wager that both fresh and recirculated air go through the filter.

 

Service manual doesn't show the airflow, but the air has to either enter or exit the blower through the filter, period. This means any setting that uses forced air in any manner will result in filtered air. Also, the telling quote is Acura warning to replace the filter every 30,000 miles/24 months or if airflow becomes less than usual.